Polyethylene homopolymer compositions having good barrier properties

ABSTRACT

A polyethylene homopolymer composition comprises: a first ethylene homopolymer having a density, d 1  of from 0.943 to 0.975 g/cm 3 , a melt index, I 2   1  of from 0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of less than 3.0; and a second ethylene homopolymer having a density, d 2  of from 0.950 to 0.985 g/cm 3 , a melt index, I 2   2  of at least 500 g/10 min, and a molecular weight distribution, M w /M n  of less than 3.0; wherein the ratio of the melt index, I 2   2  of the second ethylene homopolymer to the melt index, I 2   1  of the first ethylene homopolymer is at least 50. The polyethylene homopolymer compositions which may be nucleated have a weight average molecular weight, M w  of ≤75,000, a high load melt index, I 21  of at least 200 g/10 min, a molecular weight distribution, M w /M n  of from 4.0 to 12.0 and may be usefully employed in molding applications, such as, for example, in compression molded closures.

TECHNICAL FIELD

The present disclosure describes polyethylene homopolymer compositionswhich provide good barrier properties when used in, for example films,or closures. The polyethylene homopolymer compositions, which may benucleated, comprise a first ethylene homopolymer component and a secondethylene homopolymer component, each made with a single sitepolymerization catalyst to have a different melt index, I₂. Thepolyethylene homopolymer compositions have a relatively low weightaverage molecular weight.

BACKGROUND ART

A lot of work has been done to develop polyethylene compositionscomprising both an ethylene copolymer and an ethylene homopolymer (or anethylene copolymer having fewer short chain branches). When the ethylenecopolymer component is of higher molecular weight than the ethylenehomopolymer component (or the ethylene copolymer having fewer shortchain branches), the resultant polyethylene composition is useful in enduse applications which require high degrees of environmental resistance(see for example U.S. Pat. No. 6,809,154). Such end use applicationsinclude for example molded articles such as all-polyethylene closuresfor bottles (see for example WO 2016/135590 and U.S. Pat. Nos.9,758,653; 9,074,082; 9,475,927; 9,783,663; 9,783,664; 8,962,755;9,221,966; 9,371,442 and 8,022,143). Work has also been done to developpolyethylene compositions which comprise two ethylene homopolymercomponents where the components chosen are of relatively low andrelatively high molecular weight. These ethylene homopolymercompositions, which may have a bimodal molecular weight distributionprofile, have been usefully applied in the formation of films havinggood barrier properties (see for example U.S. Pat. Nos. 7,737,220 and9,587,093, and U.S. Pat. Appl. Pub. Nos 2008/0118749, 2009/0029182 and2011/0143155).

SUMMARY OF INVENTION

We now report a new ethylene homopolymer composition comprising a firstethylene homopolymer component and a second ethylene homopolymercomponent. The new ethylene homopolymer compositions, which may benucleated, can be usefully employed as is in various end useapplications. Alternatively, the new ethylene homopolymer compositionscan be used as a polymer blend component in a polymer composition.

An embodiment of the disclosure is a polyethylene homopolymercomposition, the polyethylene homopolymer composition comprising: (1) 10to 90 weight % of a first ethylene homopolymer having a density, d¹ offrom 0.943 to 0.975 g/cm³, a melt index, I₂ ¹ of from 0.01 to 10 g/10min, and a molecular weight distribution, Mw/Mn of less than 3.0; and(2) 90 to 10 weight % of a second ethylene homopolymer having a density,d² of from 0.950 to 0.985 g/cm³, a melt index, I₂ ² of at least 500 g/10min, and a molecular weight distribution, M_(w)/M_(n) of less than 3.0;wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least 50, and wherein the polyethylene homopolymer composition has aweight average molecular weight, M_(w) of ≤75,000, a high load meltindex, I₂₁ of at least 200 g/10 min, and a molecular weightdistribution, M_(w)/M_(n) of from 4.0 to 12.0.

In an embodiment of the disclosure, the polyethylene homopolymercomposition further comprises a nucleating agent, or a mixture ofnucleating agents.

In an embodiment of the disclosure, the polyethylene homopolymercomposition comprises a nucleating agent which is a salt of adicarboxylic acid compound.

In an embodiment of the disclosure, the polyethylene homopolymercomposition comprises from 20 to 4000 ppm of a nucleating agent or amixture of nucleating agents.

An embodiment of the disclosure is an injection molded articlecomprising the polyethylene homopolymer composition.

An embodiment of the disclosure is a compression molded articlecomprising the polyethylene homopolymer composition.

An embodiment of the disclosure is a closure (e.g. a closure forbottles) comprising the polyethylene homopolymer composition.

An embodiment of the disclosure is a film comprising the polyethylenehomopolymer composition.

An embodiment of the disclosure is a polyethylene homopolymercomposition, the polyethylene homopolymer composition comprising: (1) 10to 90 weight % of a first ethylene homopolymer having a density, d¹ offrom 0.943 to 0.975 g/cm³, a melt index, I₂ ¹ of from 0.01 to 10 g/10min, and a molecular weight distribution, Mw/Mn of less than 3.0; and(2) 90 to 10 weight % of a second ethylene homopolymer having a density,d² of from 0.950 to 0.985 g/cm³, a melt index, I₂ ² of at least 500 g/10min, and a molecular weight distribution, M_(w)/M_(n) of less than 3.0;wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least 50, and wherein the polyethylene homopolymer composition has aweight average molecular weight, M_(w) of ≤75,000, a high load meltindex, I₂ ¹ of at least 200 g/10 min, and a molecular weightdistribution, M_(w)/M_(n) of from 4.0 to 12.0; and wherein thepolyethylene homopolymer composition is made by a process comprisingcontacting at least one single site polymerization catalyst system withethylene under solution polymerization conditions in at least twopolymerization reactors.

An embodiment of the disclosure is a process to prepare a polyethylenehomopolymer composition, the polyethylene homopolymer compositioncomprising: (1) 10 to 90 weight % of a first ethylene homopolymer havinga density, d¹ of from 0.943 to 0.975 g/cm³, a melt index, I₂ ¹ of from0.01 to 10 g/10 min, and a molecular weight distribution, Mw/Mn of lessthan 3.0; and (2) 90 to 10 weight % of a second ethylene homopolymerhaving a density, d² of from 0.950 to 0.985 g/cm³, a melt index, I₂ ² ofat least 500 g/10 min, and a molecular weight distribution, M_(w)/M_(n)of less than 3.0; wherein the ratio of the melt index, I₂ ² of thesecond ethylene homopolymer to the melt index, I₂ ¹ of the firstethylene homopolymer is at least 50, and wherein the polyethylenehomopolymer composition has a weight average molecular weight, M_(w) of≤75,000, a high load melt index, I₂ ¹ of at least 200 g/10 min, and amolecular weight distribution, M_(w)/M_(n) of from 4.0 to 12.0; theprocess comprising contacting at least one single site polymerizationcatalyst system with ethylene under solution polymerization conditionsin at least two polymerization reactors.

In an embodiment of the disclosure, the at least two polymerizationreactors comprise a first reactor and a second reactor configured inseries.

An embodiment of the disclosure is a polymer composition comprising from1 to 100 percent by weight of a polyethylene homopolymer composition,the polyethylene homopolymer composition comprising: (1) 10 to 90 weight% of a first ethylene homopolymer having a density, d¹ of from 0.943 to0.975 g/cm³, a melt index, I₂ ¹ of from 0.01 to 10 g/10 min, and amolecular weight distribution, M_(w)/M_(n) of less than 3.0; and (2) 90to 10 weight % of a second ethylene homopolymer having a density, d² offrom 0.950 to 0.985 g/cm³, a melt index, I₂ ² of at least 500 g/10 min,and a molecular weight distribution, M_(w)/M_(n) of less than 3.0;wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least 50, and wherein the polyethylene homopolymer composition has aweight average molecular weight, M_(w) of ≤75,000, a high load meltindex, I₂₁ of at least 200 g/10 min, and a molecular weightdistribution, M_(w)/M_(n) of from 4.0 to 12.0.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows the gel permeation chromatographs (GPC) with refractiveindex detection of polyethylene compositions (Examples 1 and 2) madeaccording to the present disclosure and for two comparative polyethylenecompositions (Example 3 and 4).

FIG. 2 shows the oxygen transmission rates (OTR) of compression moldedfilms made from nucleated polyethylene compositions (Examples 1* and 2*)according to the present disclosure vs. the weight average molecularweight (Mw) of the nucleated polyethylene compositions (Examples 1* and2*). FIG. 2 also shows the oxygen transmission rates (OTR) ofcompression molded films made from comparative nucleated polyethylenecompositions (Examples 3 and 4) vs. the weight average molecular weight(Mw) of the comparative nucleated polyethylene compositions (Examples 3and 4).

FIG. 3 shows the water vapor transmission rates (WVTR) of compressionmolded films made from nucleated polyethylene compositions (Examples 1*and 2*) according to the present disclosure vs. the weight averagemolecular weight (Mw) of the nucleated polyethylene compositions(Examples 1* and 2*). FIG. 3 also shows the water vapor transmissionrates (WVTR) of compression molded films made from comparative nucleatedpolyethylene compositions (Examples 3 and 4) vs. the weight averagemolecular weight (Mw) of the comparative nucleated polyethylenecompositions (Examples 3 and 4).

FIG. 4 shows the oxygen transmission rates (OTR) of injection moldedclosures made from nucleated polyethylene compositions (Examples 1* and2*) according to the present disclosure vs. the weight average molecularweight (Mw) of the nucleated polyethylene compositions (Examples 1* and2*). FIG. 4 also shows the oxygen transmission rates (OTR) of injectionmolded closures made from comparative nucleated polyethylenecompositions (Examples 3 and 4) vs. the weight average molecular weight(Mw) of the comparative nucleated polyethylene compositions (Examples 3and 4).

DESCRIPTION OF EMBODIMENTS

By the terms “ethylene homopolymer” or “polyethylene homopolymer”, or“ethylene homopolymer composition” it is meant that the polymer referredto is the product of a polymerization process, where only ethylene wasdeliberately added as a polymerizable olefin. In contrast, the terms“ethylene copolymer” or “polyethylene copolymer”, or “polyethylenecopolymer composition” mean that the polymer referred to is the productof a polymerization process, where ethylene and one or more than onealpha olefin comonomer were deliberately added as polymerizable olefins.

The term “unimodal” is herein defined to mean there will be only onesignificant peak or maximum evident in a GPC-curve. A unimodal profileincludes a broad unimodal profile. Alternatively, the term “unimodal”connotes the presence of a single maxima in a molecular weightdistribution curve generated according to the method of ASTM D6474-99.In contrast, by the term “bimodal” it is meant that there will be asecondary peak or shoulder evident in a GPC-curve which represents ahigher or lower molecular weight component (i.e. the molecular weightdistribution, can be said to have two maxima in a molecular weightdistribution curve). Alternatively, the term “bimodal” connotes thepresence of two maxima in a molecular weight distribution curvegenerated according to the method of ASTM D6474-99. The term“multi-modal” denotes the presence of two or more maxima in a molecularweight distribution curve generated according to the method of ASTMD6474-99.

In an embodiment of the disclosure a polymer composition comprises from1 to 100 percent by weight of a polyethylene homopolymer composition.

In an embodiment of the disclosure, a polyethylene homopolymercomposition comprises two components, (1) a first ethylene homopolymer;and (2) a second ethylene homopolymer which is different from the firsthomopolymer.

In an embodiment of the disclosure, a polyethylene homopolymercomposition comprises only two polymer components, (1) a first ethylenehomopolymer; and (2) a second ethylene homopolymer which is differentfrom the first homopolymer.

In an embodiment of the disclosure, a polyethylene homopolymercomposition further comprises a nucleating agent.

The first and second ethylene homopolymers are defined further below.

The First Ethylene Homopolymer

In an embodiment of the disclosure the first ethylene homopolymer ismade using a single site polymerization catalyst.

In an embodiment of the disclosure the first ethylene homopolymer ismade using a single site polymerization catalyst in a solution phasepolymerization process.

In an embodiment of the disclosure the first ethylene homopolymer ismade using a single site polymerization catalyst to polymerize onlyethylene as a deliberately added monomer in a solution phasepolymerization process.

In an embodiment of the disclosure, the melt index, I₂ ¹ of the firstethylene homopolymer is less than the melt index, I₂ ² of secondethylene homopolymer.

In embodiments of the disclosure the first ethylene homopolymer has amelt index, I₂ ¹ of ≤20.0 g/10 min, or ≤15.0 g/10 min, or ≤10.0 g/10min. In another embodiment of the disclosure, the first ethylenehomopolymer has a melt index, I₂ ¹ of from 0.01 to 15.0 g/10 min,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the melt index, I₂ ¹ of the first ethylene homopolymer maybe from 0.01 to 10.0 g/10 min, or from 0.01 to 7.5 g/10 min, or from0.01 to 5.0 g/10 min, or from 0.01 to 3.0 g/10 min, or from 0.1 to 15.0g/10 min, or from 0.1 to 10.0 g/10 min, or from 0.1 to 5.0 g/10 min, orfrom 0.1 to 3.0 g/10 min.

In an embodiment of the disclosure, the first ethylene homopolymer has amelt flow ratio, I₂₁/I₂ of less than 25, or less than 23, or less than20.

In an embodiment of the disclosure, the first ethylene homopolymer has aweight average molecular weight, Mw of from 40,000 to 250,000 g/mol,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the first ethylene homopolymer has a weight averagemolecular weight, Mw of from 50,000 to 200,000 g/mol, or from 60,000 to175,000 g/mol, or from 60,000 to 150,000 g/mol, or from 50,000 to150,000 g/mol, or from 50,000 to 130,000 g/mol, or from 60,000 to130,000 g/mol.

In embodiments of the disclosure, the first ethylene homopolymer has amolecular weight distribution, M_(w)/M_(n) of ≤3.0, or <3.0, or ≤2.7, or<2.7, or ≤2.5, or <2.5, or ≤2.3, or <2.3, or ≤2.1, or <2.1 or about 2.In another embodiment of the disclosure, the first ethylene homopolymerhas a molecular weight distribution, M_(w)/M_(n) of from 1.7 to 3.0,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the first ethylene homopolymer has a molecular weightdistribution, M_(w)/M_(n) of from 1.8 to 2.7, or from 1.8 to 2.5, orfrom 1.8 to 2.3, or from 1.9 to 2.1.

In an embodiment of the disclosure, the density, d¹ of the firsthomopolymer is less than the density, d² of the second ethylenehomopolymer.

In an embodiment of the disclosure, the first ethylene homopolymer has adensity, d¹ of from 0.930 to 0.985 g/cm³, including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the first ethylenehomopolymer has a density, d¹ of from 0.930 to 0.980 g/cm³, or from0.930 to 0.975 g/cm³, or from 0.935 to 0.980 g/cm³, or from 0.940 to0.980 g/cm³, or from 0.940 to 0.975 g/cm³, or from 0.943 to 0.980 g/cm³,or from 0.943 to 0.975 g/cm³, or from 0.943 to 0.970 g/cm³, or from0.943 to 0.965 g/cm³, or from 0.945 to 0.980 g/cm³, or from 0.945 to0.975 g/cm³, or from 0.945 to 0.970 g/cm³, or from 0.945 to 0.965 g/cm³,or from 0.946 to 0.980 g/cm³, or from 0.946 to 0.975 g/cm³, or from0.946 to 0.970 g/cm³, or from 0.946 to 0.965 g/cm³, or from 0.940 to0.962 g/cm³, or from 0.940 to 0.960 g/cm³, or from 0.943 to 0.962 g/cm³.

In embodiments of the disclosure, the weight percent (wt %) of the firstethylene homopolymer in the polyethylene homopolymer composition (i.e.the weight percent of the first ethylene homopolymer based on the totalweight of the first and second ethylene homopolymers) may be from about5 wt % to about 95 wt %, including any narrower ranges within this rangeand any values encompassed by these ranges. For example, in embodimentsof the disclosure, the weight percent (wt %) of the first ethylenehomopolymer in the polyethylene homopolymer composition may be fromabout 5 wt % to about 90 wt %, or from about 10 wt % to about 90 wt %,or from about 15 to about 80 wt %, or from about 20 wt % to about 80 wt%, or from about 25 wt % to about 75 wt %, or from about 30 wt % toabout 70 wt %, or from about 35 wt % to about 65 wt %, or from about 40wt % to about 70 wt %, or from about 45 wt % to about 65 wt %, or fromabout 50 wt % to about 60 wt %.

The Second Ethylene Homopolymer

In an embodiment of the disclosure the second ethylene homopolymer ismade using a single site polymerization catalyst.

In an embodiment of the disclosure the second ethylene homopolymer ismade using a single site polymerization catalyst in a solution phasepolymerization process.

In an embodiment of the disclosure the second ethylene homopolymer ismade using a single site polymerization catalyst to polymerize onlyethylene as a deliberately added monomer in a solution phasepolymerization process.

In an embodiment of the disclosure, the melt index, I₂ ² of the secondethylene homopolymer is greater than the melt index, I₂ ¹ of firstethylene homopolymer.

In embodiments of the disclosure, the ratio of the melt index, I₂ ² ofthe second ethylene homopolymer to the melt index, I₂ ¹ of the firstethylene homopolymer is at least 25, or at least 50, or at least 100, orat least 1,000, or at least 5,000, or at least 7,500.

In an embodiment of the disclosure, the ratio of the melt index, I₂ ² ofthe second ethylene homopolymer to the melt index, I₂ ¹ of the firstethylene homopolymer is from 25 to 30,000, including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the ratio of the melt index,I₂ ² of the second ethylene homopolymer to the melt index, I₂ ¹ of thefirst ethylene homopolymer may be from 50 to 30,000, or from 100 to30,000, or from 1000 to 30,000, or from 5,000 to 30,000, or from 50 to25,000, or from 100 to 25,000, or from 1,000 to 25,000, or from 5,000 to25,000, or from 7,500 to 30,000, or from 7,500 to 25,000.

In embodiments of the disclosure the second ethylene homopolymer has amelt index, I₂ ² of at least 250 g/10 min, or at least 500 g/10 min, orat least 1,000 g/10 min, or at least 5,000 g/10 min, or at least 7,500g/10 min, or at least 10,000 g/10 min. In another embodiment of thedisclosure, the second ethylene homopolymer has a melt index, I₂ ² offrom 250 to 20,000 g/10 min, including any narrower ranges within thisrange and any values encompassed by these ranges. For example, inembodiments of the disclosure, the melt index, I₂ ² of the secondethylene homopolymer may be from 500 to 15,000 g/10 min, or from 1000 to17,500 g/10 min, or from 2,500 to 20,000 g/10 min, or from 5,000 to20,000 g/10 min, or from 5,000 to 17,500 g/10 min, or from 1000 to20,000 g/10 min, or from 2,500 to 17,500 g/10 min, or from 7,500 to20,000 g/10 min, or from 7,500 to 17,500 g/10 min, or from 7,500 to15,000 g/10 min, or from 5,000 to 15,000 g/10 min.

In an embodiment of the disclosure, the second ethylene homopolymer hasa melt flow ratio, I₂₁/I₂ of less than 25, or less than 23, or less than20.

In an embodiment of the disclosure, the second ethylene homopolymer hasa weight average molecular weight, Mw of ≤65,000 g/mol, or ≤55,000g/mol, or ≤45,000 g/mol, or ≤35,000 g/mol, or ≤25,000 g/mol, or ≤15,000g/mol, or ≤10,000 g/mol. In another embodiment the second ethylenehomopolymer has a weight average molecular weight, Mw of from 2,500 to70,000 g/mol, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, the second ethylene homopolymer has a weight averagemolecular weight, Mw of from 2,500 to 60,000 g/mol, or from 2,500 to50,000 g/mol, or from 2,500 to 40,000 g/mol, or from 2,500 to 30,000g/mol, or from 2,500 to 20,000 g/mol, or from 2,500 to 15,000 g/mol, orfrom 5,000 to 30,000 g/mol, or from 5,000 to 20,000 g/mol, or from 5,000to 25,000 g/mol, or from 2,500 to 25,000 g/mol.

In embodiments of the disclosure, the second ethylene homopolymer has amolecular weight distribution, M_(w)/M_(n) of ≤3.0, or <3.0, or ≤2.7, or<2.7, or ≤2.5, or <2.5, or ≤2.3, or ≤2.3, or <2.1, or <2.1 or about 2.In another embodiment of the disclosure, the second ethylene homopolymerhas a molecular weight distribution, M_(w)/M_(n) of from 1.7 to 3.0,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the second ethylene homopolymer has a molecular weightdistribution, M_(w)/M_(n) of from 1.8 to 2.7, or from 1.8 to 2.5, orfrom 1.8 to 2.3, or from 1.9 to 2.1.

In an embodiment of the disclosure, the density, d² of the secondhomopolymer is greater than the density, d¹ of the first ethylenehomopolymer.

In an embodiment of the disclosure, the density, d² of the secondethylene homopolymer is less than 0.035 g/cm³ greater than the density,d¹ of the first ethylene homopolymer. In an embodiment of thedisclosure, the density, d² of the second ethylene homopolymer is lessthan 0.030 g/cm³ greater than the density, d¹ of the first ethylenehomopolymer. In an embodiment of the disclosure, the density, d² of thesecond ethylene homopolymer is less than 0.025 g/cm³ greater than thedensity, d¹ of the first ethylene homopolymer.

In an embodiment of the disclosure, the second ethylene homopolymer hasa density, d² of from 0.940 to 0.985 g/cm³, including any narrowerranges within this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the second ethylenehomopolymer has a density, d² of from 0.943 to 0.985 g/cm³, or from0.945 to 0.985 g/cm³, or from 0.950 to 0.985 g/cm³, or from 0.950 to0.980 g/cm³, or from 0.953 to 0.985 g/cm³, or from 0.953 to 0.980 g/cm³,or from 0.955 to 0.985 g/cm³, or from 0.955 to 0.980 g/cm³, or from0.955 to 0.975 g/cm³, or from 0.950 to 0.975 g/cm³, or from 0.957 to0.985 g/cm³, or from 0.957 to 0.980 g/cm³, or from 0.957 to 0.975 g/cm³,or from 0.959 to 0.985 g/cm³, or from 0.959 to 0.980 g/cm³, or from0.959 to 0.975 g/cm³.

In embodiments of the disclosure, the weight percent (wt %) of thesecond ethylene homopolymer in the polyethylene homopolymer composition(i.e. the weight percent of the second ethylene homopolymer based on thetotal weight of the first and second ethylene homopolymers) may be fromabout 5 wt % to about 95 wt %, including any narrower ranges within thisrange and any values encompassed by these ranges. For example, inembodiments of the disclosure, the weight percent (wt %) of the secondethylene homopolymer in the polyethylene homopolymer composition may befrom about 5 wt % to about 90 wt %, or from about 10 wt % to about 90 wt%, or from about 15 to about 80 wt %, or from about 20 wt % to about 80wt %, or from about 25 wt % to about 75 wt %, or from about 30 wt % toabout 70 wt %, or from about 35 wt % to about 65 wt %, or from about 35wt % to about 60 wt %, or from about 35 wt % to about 55 wt %, or fromabout 40 wt % to about 55 wt %, or from about 40 wt % to about 50 wt %.

The Polyethylene Homopolymer Composition

In an embodiment of the disclosure, the polyethylene homopolymercomposition will comprise a first ethylene homopolymer and a secondethylene homopolymer (each as defined herein).

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a bimodal profile (i.e. molecular weight distribution)in a gel permeation chromatography (GPC) analysis.

In an embodiment of the disclosure, the polyethylene composition has abimodal profile in a gel permeation chromatograph generated according tothe method of ASTM D6474-99.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a weight average molecular weight, Mw of ≤100,000 g/mol,or ≤75,000 g/mol, or <70,000 g/mol, or ≤65,000 g/mol, or <65,000 g/molor ≤60,000 g/mol, or <60,000 g/mol. In another embodiment, thepolyethylene homopolymer composition has a weight average molecularweight, Mw of from 10,00 to 75,000 g/mol, including any narrower rangeswithin this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the polyethylene homopolymercomposition has a weight average molecular weight, Mw of from 15,000 to75,000 g/mol, or from 15,000 to 70,000 g/mol, or from 20,000 to 75,000g/mol, or from 25,000 to 75,000 g/mol, or from 30,000 to 75,000 g/mol,or from 25,000 to 70,000 g/mol, or from 25,000 to 65,000 g/mol, or from25,000 to 60,000 g/mol, or from 30,000 to 75,000 g/mol, or from 30,000to 70,000 g/mol, or from 30,000 to 65,000 g/mol, or from 35,000 to75,000 g/mol, or from 35,000 to 70,000 g/mol, or from 35,000 to 65,000g/mol.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a number average molecular weight, M_(n) of ≤50,000g/mol, or ≤40,000 g/mol, or <40,000 g/mol, or ≤30,000 g/mol, or <30,000g/mol, or ≤20,000 g/mol, or <20,000 g/mol, or ≤15,000 g/mol, or <15,000g/mol, or ≤10,000 g/mol, or <10,000 g/mol. In another embodiment of thedisclosure, the polyethylene homopolymer composition has a numberaverage molecular weight, M_(n) of from 1,000 to 50,000 g/mol, includingany narrower ranges within this range and any values encompassed bythese ranges. For example, in embodiments of the disclosure, thepolyethylene homopolymer composition has a number average molecularweight, M_(n) of from 1,000 to 40,000 g/mol, or from 1,000 to 30,000g/mol, or from 1,000 to 20,000 g/mol, or from 1,000 to 15,000 g/mol, orfrom 1,000 to 10,000 g/mol, or from 2,500 to 35,000 g/mol, or from 2,500to 30,000 g/mol, or from 2,500 to 25,000 g/mol, or from 2,500 to 20,000g/mol, or from 2,500 to 15,000 g/mol, or from 2,500 to 10,000 g/mol, orfrom 5,000 to 35,000 g/mol, or from 5,000 to 30,000 g/mol, or from 5,000to 25,000 g/mol, or from 5,000 to 20,000 g/mol, or from 5,000 to 15,000g/mol, or from 5,000 to 10,000 g/mol.

In embodiments of the disclosure, the polyethylene homopolymercomposition has a molecular weight distribution, M_(w)/M_(n) of from 3.0to 15.0, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the polyethylene homopolymer composition has a molecularweight distribution, M_(w)/M_(n) of from 3.5 to 15.0, or from 3.0 to12.0, or from 4.0 to 15.0, or from 4.0 to 12.0, or from 4.0 to 10.0, orfrom 4.0 to 9.0.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a density of from 0.943 to 0.987 g/cm³, including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, the polyethylenehomopolymer composition has a density of from 0.945 to 0.985 g/cm³, orfrom 0.947 to 0.985 g/cm³, or from 0.950 to 0.985 g/cm³, or from 0.953to 0.985 g/cm³, or from 0.955 to 0.985 g/cm³, or from 0.961 to 0.085g/cm³, or from 0.945 to 0.980 g/cm³, or from 0.947 to 0.980 g/cm³, orfrom 0.950 to 0.980 g/cm³, or from 0.951 to 0.980 g/cm³, or from 0.953to 0.980 g/cm³, or from 0.955 to 0.980 g/cm³, or from 0.961 to 0.980g/cm³, or from 0.945 to 0.975 g/cm³, or from 0.947 to 0.975 g/cm³, orfrom 0.950 to 0.975 g/cm³, or from 0.951 to 0.975 g/cm³, or from 0.953to 0.975 g/cm³, or from 0.955 to 0.975 g/cm³, or from 0.961 to 0.975g/cm³, or from 0.945 to 0.970 g/cm³, or from 0.947 to 0.970 g/cm³, orfrom 0.950 to 0.970 g/cm³, or from 0.951 to 0.970 g/cm³, or from 0.953to 0.970 g/cm³, or from 0.955 to 0.970 g/cm³, or from 0.961 to 0.970g/cm³.

In embodiments of the disclosure, the polyethylene homopolymercomposition has a density of ≥0.950 g/cm³, or >0.950 g/cm³, or ≥0.955g/cm³, or >0.955 g/cm³, or ≥0.960 g/cm³, or >0.960 g/cm³, or ≥0.965g/cm³, or >0.965 g/cm³.

In embodiments of the disclosure the polyethylene homopolymercomposition has a melt index, I₂ of at least 1.0 g/10 min (≥1.0 g/10min), or at least 3.0 g/10 min (≥3.0 g/10 min), or at least 5.0 g/10 min(≥5.0 g/10 min), or at least 7.5 g/10 min (≥7.5 g/10 min), or at least10.0 g/10 min (≥10.0 g/10 min), or greater than 3.0 g/10 min (≥3.0 g/10min), or greater than 5.0 g/10 min (≥5.0 g/10 min), or greater than 7.5g/10 min (≥7.5 g/10 min), or greater than 10.0 g/10 min (>10.0 g/10min). In another embodiment of the disclosure, the polyethylenehomopolymer composition has a melt index, I₂ of from 1.0 to 250 g/10min, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the melt index, 12 of the polyethylene homopolymercomposition may be from 1.0 to 200 g/10 min, or from 1.0 to 150 g/10min, or from 1 to 100 g/10 min, or from 1 to 50 g/10 min, or from 10.0to 200 g/10 min, or from 10.0 to 150 g/10 min, or from 10.0 to 100 g/10min, or from 10.0 to 50 g/10 min, or from 7.5 to 200 g/10 min, or from7.5 to 150 g/10 min, or from 7.5 to 100 g/10 min, or from 7.5 to 50 g/10min, or from 5.0 to 200 g/10 min, or from 5.0 to 150 g/10 min, or from5.0 to 100 g/10 min, or from 5.0 to 75 g/10 min, or from 5.0 to 50 g/10min, or from 5.0 to 40 g/10 min, or from 3.0 to 100 g/10 min, or from3.0 to 75 g/10 min, or from 3.0 to 50 g/10 min, or from 3.0 to 40 g/10min, or from 7.5 to 40 g/10 min, or from 7.5 to 30 g/10 min.

In embodiments of the disclosure the polyethylene homopolymercomposition has a high load melt index, I₂₁ of at least 200 g/10 min(≥200 g/10 min), or at least 250 g/10 min (≥250 g/10 min), or at least300 g/10 min (≥300 g/10 min), or at least 350 g/10 min (≥350 g/10 min),or at least 400 g/10 min (≥400 g/10 min), or greater than 200 g/10 min(>200 g/10 min), or greater than 250 g/10 min (>250 g/10 min), orgreater than 300 g/10 min (>300 g/10 min), or greater than 350 g/10 min(>350 g/10 min), or greater than 400 g/10 min (>400 g/10 min). Inanother embodiment of the disclosure, the polyethylene homopolymercomposition has a high load melt index, I₂₁ of from 200 to 2500 g/10min, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, the high load melt index, I₂₁ of the polyethylenehomopolymer composition may be from 200 to 2,000 g/10 min, or from 200to 1,500 g/10 min, from 200 to 1,000 g/10 min, or from 200 to 800 g/10min.

In embodiments of the disclosure the polyethylene homopolymercomposition has a melt flow ratio, I₂₁/I₂ of ≤50, or <50, or ≤45, or<40, or ≤35, or <35. In another embodiment of the disclosure, thepolyethylene homopolymer composition has a melt flow ratio, I₂₁/I₂ offrom 12 to 75, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, the polyethylene homopolymer composition has a melt flowratio, I₂₁/I₂ of from 14 to 60, or from 14 to 50, or from 16 to 40, orfrom 18 to 50, or from 18 to 40, or from 20 to 50, or from 20 to 45, orfrom 20 to 40.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a stress exponent, defined asLog₁₀[I₆/I₂]/Log₁₀[6.48/2.16], which is ≤1.40. In further embodiments ofthe disclosure the polyethylene composition has a stress exponent,Log₁₀[I₆/I₂]/Log₁₀ [6.48/2.16] of less than 1.38, or less than 1.36, orless than 1.34, or less than 1.32, or less than 1.30, or less than 1.28.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a shear viscosity at about 10⁵ s⁻¹ (240° C.) of lessthan about 8 Pa·s. In an embodiment of the disclosure, the polyethylenehomopolymer composition has a shear viscosity at about 10⁵ s⁻¹ (240° C.)of from about 1 to about 8 Pa·s including any narrower ranges withinthis range and any values encompassed by these ranges. For example, inembodiments of the disclosure, the polyethylene homopolymer compositionhas a shear viscosity at about 10⁵ s⁻¹ (240° C.) of from about 2 toabout 6 Pa·s, or from about 2 to about 5 Pa·s, or from about 3 to about5 Pa·s.

In an embodiment of the invention, the shear viscosity ratio,SVR(_(100,100000)) at 240° C. of the polyethylene homopolymercomposition can be from about 10 to about 80, including any narrowerranges within this range and any values encompassed by these ranges. Forexample, in embodiments of the disclosure, the shear viscosity ratio,SVR(_(100,100000)) at 240° C. of the polyethylene homopolymercomposition can be from about 20 to about 80, or from about 30 to about80, or from about 20 to about 70, or from about 30 to about 70.

In an embodiment of the disclosure, the polyethylene homopolymercomposition has a hexane extractable value of ≤5.5 weight percent, orless than 4.5 wt %, or less than 3.5 wt %, or less than 2.5 wt %, orless than 2.0 wt %, or less than 1.5 wt %, or less than 1.0 wt %, orless than 0.75 wt %.

In an embodiment of the disclosure, the polyethylene homopolymercomposition or a molded article (or plaque) made from the polyethylenehomopolymer composition, has an environment stress crack resistance ESCRCondition B at 100% of fewer than 50 hours, or fewer than 40 hours, orfewer than 30 hours, or fewer than 20 hours, or fewer than 10 hours, orfewer than 5 hours, as measured according to ASTM D1693 (at 100% IGEPALand 50° C. under condition B).

The polyethylene homopolymer composition of this disclosure can be madeusing any conventional blending method such as but not limited tophysical blending and in-situ blending by polymerization in multireactor systems. For example, it is possible to perform the mixing ofthe first ethylene homopolymer with the second ethylene homopolymer bymolten mixing of the two preformed polymers. Preferred are processes inwhich the first and second ethylene homopolymers are prepared in atleast two sequential polymerization stages, however, both in-series oran in-parallel dual reactor process are contemplated for use in thecurrent disclosure. Gas phase, slurry phase or solution phase reactorsystems may be used, with solution phase reactor systems beingpreferred.

Mixed catalyst single reactor systems may also be employed to make thepolyethylene homopolymer compositions of the present disclosure.

In an embodiment of the current disclosure, a dual reactor solutionpolymerization process is used as has been described in for example U.S.Pat. No. 6,372,864 and U.S. Pat. Appl. No. 20060247373A1 which areincorporated herein by reference.

Generally, the catalysts used in the current disclosure will be socalled single site catalysts based on a group 4 metal having at leastone cyclopentadienyl ligand. Examples of such catalysts which includemetallocenes, constrained geometry catalysts and phosphinimine catalystsare typically used in combination with activators selected frommethylaluminoxanes, boranes or ionic borate salts and are furtherdescribed in U.S. Pat. Nos. 3,645,992; 5,324,800; 5,064,802; 5,055,438;6,689,847; 6,114,481 and 6,063,879. Such single site catalysts aredistinguished from traditional Ziegler-Natta or Phillips catalysts whichare also well known in the art. In general, single site catalystsproduce ethylene homopolymers having a molecular weight distribution(M_(w)/M_(n)) of less than about 3.0, or in some cases less than about2.5.

In embodiments of the disclosure, a single site catalyst which gives anethylene homopolymer having a molecular weight distribution(M_(w)/M_(n)) of less than about 3.0, or less than about 2.7, or lessthan about 2.5, is used in the preparation of each of the first and thesecond ethylene homopolymers.

In an embodiment of the disclosure, the first and second ethylenehomopolymers are prepared using an organometallic complex of a group 3,4 or 5 metal that is further characterized as having a phosphinimineligand. Such a complex, when active toward olefin polymerization, isknown generally as a phosphinimine (polymerization) catalyst. Somenon-limiting examples of phosphinimine catalysts can be found in U.S.Pat. Nos. 6,342,463; 6,235,672; 6,372,864; 6,984,695; 6,063,879;6,777,509 and 6,277,931 all of which are incorporated by referenceherein.

Some non-limiting examples of metallocene catalysts can be found in U.S.Pat. Nos. 4,808,561; 4,701,432; 4,937,301; 5,324,800; 5,633,394;4,935,397; 6,002,033 and 6,489,413, which are incorporated herein byreference. Some non-limiting examples of constrained geometry catalystscan be found in U.S. Pat. Nos. 5,057,475; 5,096,867; 5,064,802;5,132,380; 5,703,187 and 6,034,021, all of which are incorporated byreference herein in their entirety.

In an embodiment of the disclosure, use of a single site catalyst thatdoes not produce long chain branching (LCB) is preferred. Hexyl (C6)branches detected by NMR are excluded from the definition of a longchain branch in the present disclosure.

Without wishing to be bound by any single theory, long chain branchingcan increase viscosity at low shear rates, thereby negatively impactingcycle times during the manufacture of caps and closures, such as duringthe process of compression molding. Long chain branching may bedetermined using ¹³C NMR methods and may be quantitatively assessedusing the method disclosed by Randall in Rev. Macromol. Chem. Phys. C29(2 and 3), p. 285.

In an embodiment of the disclosure, the polyethylene homopolymercomposition will contain fewer than 0.3 long chain branches per 1000carbon atoms. In another embodiment of the disclosure, the polyethylenehomopolymer composition will contain fewer than 0.01 long chain branchesper 1000 carbon atoms.

In an embodiment of the disclosure, the polyethylene homopolymercomposition (defined as above) is prepared by contacting only ethyleneas a polymerizable monomer with a polymerization catalyst under solutionphase polymerization conditions in at least two polymerization reactors(for an example of solution phase polymerization conditions see forexample U.S. Pat. Nos. 6,372,864; 6,984,695 and U.S. App. No.20060247373A1 which are incorporated herein by reference).

In an embodiment of the disclosure, the polyethylene homopolymercomposition is prepared by contacting at least one single sitepolymerization catalyst system (comprising at least one single sitecatalyst and at least one activator) with only ethylene as apolymerizable monomer under solution polymerization conditions in atleast two polymerization reactors.

In an embodiment of the disclosure, a group 4 single site catalystsystem, comprising a single site catalyst and an activator, is used in asolution phase dual reactor system to prepare a polyethylene homopolymercomposition by polymerization of ethylene.

In an embodiment of the disclosure, a group 4 phosphinimine catalystsystem, comprising a phosphinimine catalyst and an activator, is used ina solution phase dual reactor system to prepare a polyethylenehomopolymer composition by polymerization of ethylene.

In an embodiment of the disclosure, a solution phase dual reactor systemcomprises two solution phase reactors connected in series.

In an embodiment of the disclosure, a polymerization process to preparethe polyethylene homopolymer composition comprises contacting at leastone single site polymerization catalyst system (comprising at least onesingle site catalyst and at least one activator) with ethylene undersolution polymerization conditions in at least two polymerizationreactors.

In an embodiment of the disclosure, a polymerization process to preparethe polyethylene homopolymer composition comprises contacting at leastone single site polymerization catalyst system with ethylene undersolution polymerization conditions in a first reactor and a secondreactor configured in series.

The production of the polyethylene homopolymer composition of thepresent disclosure will typically include an extrusion or compoundingstep. Such steps are well known in the art.

The polyethylene homopolymer composition can comprise further polymercomponents in addition to the first and second ethylene homopolymers.Such polymer components include polymers made in situ or polymers addedto the polymer composition during an extrusion or compounding step.

Optionally, additives can be added to the polyethylene homopolymercomposition. Additives can be added to the polyethylene homopolymercomposition during an extrusion or compounding step, but other suitableknown methods will be apparent to a person skilled in the art. Theadditives can be added as is or as part of a separate polymer component(i.e. not the first or second ethylene homopolymers described herein) oradded as part of a masterbatch (optionally during an extrusion orcompounding step). Suitable additives are known in the art and includebut are not-limited to antioxidants, phosphites and phosphonites,nitrones, antacids, UV light stabilizers, UV absorbers, metaldeactivators, dyes, fillers and reinforcing agents, nano-scale organicor inorganic materials, antistatic agents, lubricating agents such ascalcium stearates, slip additives such as erucamide or behenamide, andnucleating agents (including nucleators, pigments or any other chemicalswhich may provide a nucleating effect to the polyethylene homopolymercomposition). The additives that can be optionally added are typicallyadded in amount of up to 20 weight percent (wt %).

One or more nucleating agent(s) may be introduced into the polyethylenehomopolymer composition by kneading a mixture of the polymer, usually inpowder or pellet form, with the nucleating agent, which may be utilizedalone or in the form of a concentrate containing further additives suchas stabilizers, pigments, antistatics, UV stabilizers and fillers. Itshould be a material which is wetted or absorbed by the polymer, whichis insoluble in the polymer and of melting point higher than that of thepolymer, and it should be homogeneously dispersible in the polymer meltin as fine a form as possible (1 to 10 μm). Compounds known to have anucleating capacity for polyolefins include salts of aliphatic monobasicor dibasic acids or arylalkyl acids, such as sodium succinate, oraluminum phenylacetate; and alkali metal or aluminum salts of aromaticor alicyclic carboxylic acids such as sodium β-naphthoate, or sodiumbenzoate.

Some non-limiting examples of nucleating agents which are commerciallyavailable and which may be added to the polyethylene homopolymercomposition are dibenzylidene sorbital esters (such as the products soldunder the trademark MILLAD® 3988 by Milliken Chemical and IRGACLEAR® byCiba Specialty Chemicals). Further non-limiting examples of nucleatingagents which may be added to the polyethylene homopolymer compositioninclude the cyclic organic structures disclosed in U.S. Pat. No.5,981,636 (and salts thereof, such as disodium bicyclo [2.2.1] heptenedicarboxylate); the saturated versions of the structures disclosed inU.S. Pat. No. 5,981,636 (as disclosed in U.S. Pat. No. 6,465,551; Zhaoet al., to Milliken); the salts of certain cyclic dicarboxylic acidshaving a hexahydrophthalic acid structure (or “HHPA” structure) asdisclosed in U.S. Pat. No. 6,599,971 (Dotson et al., to Milliken); andphosphate esters, such as those disclosed in U.S. Pat. No. 5,342,868 andthose sold under the trade names NA-11 and NA-21 by Asahi Denka Kogyo,cyclic dicarboxylates and the salts thereof, such as the divalent metalor metalloid salts, (particularly, calcium salts) of the HHPA structuresdisclosed in U.S. Pat. No. 6,599,971. For clarity, the HHPA structuregenerally comprises a ring structure with six carbon atoms in the ringand two carboxylic acid groups which are substituents on adjacent atomsof the ring structure. The other four carbon atoms in the ring may besubstituted, as disclosed in U.S. Pat. No. 6,599,971. An example is1,2-cyclohexanedicarboxylicacid, calcium salt (CAS registry number491589-22-1). Still further non-limiting examples of nucleating agentswhich may be added to the polyethylene homopolymer composition includethose disclosed in WO2015042561, WO2015042563, WO2015042562 andWO2011050042.

Many of the above described nucleating agents may be difficult to mixwith the polyethylene homopolymer composition that is being nucleatedand it is known to use dispersion aids, such as for example, zincstearate, to mitigate this problem.

In an embodiment of the disclosure, the nucleating agents are welldispersed in the polyethylene homopolymer composition.

In an embodiment of the disclosure, the amount of nucleating agent usedis comparatively small—from 100 to 4000 parts by million per weight(based on the weight of the polyethylene homopolymer composition) so itwill be appreciated by those skilled in the art that some care must betaken to ensure that the nucleating agent is well dispersed. In anembodiment of the disclosure, the nucleating agent is added in finelydivided form (less than 50 microns, especially less than 10 microns) tothe polyethylene homopolymer composition to facilitate mixing. This typeof “physical blend” (i.e. a mixture of the nucleating agent and theresin in solid form) is in some embodiments preferable to the use of a“masterbatch” of the nucleator (where the term “masterbatch” refers tothe practice of first melt mixing the additive—the nucleator, in thiscase—with a small amount of the polyethylene homopolymercomposition—then melt mixing the “masterbatch” with the remaining bulkof the polyethylene homopolymer composition).

In an embodiment of the disclosure, an additive such as nucleating agentmay be added to the polyethylene homopolymer composition by way of a“masterbatch”, where the term “masterbatch” refers to the practice offirst melt mixing the additive (e.g. a nucleator) with a small amount ofthe polyethylene homopolymer composition, followed by melt mixing the“masterbatch” with the remaining bulk of the polyethylene homopolymercomposition.

In an embodiment of the disclosure, the polyethylene homopolymercomposition further comprises a nucleating agent.

In an embodiment of the disclosure, the polyethylene homopolymercomposition comprises from 20 to 4,000 ppm (i.e. parts per million,based on the total weight of the first and the second ethylenehomopolymers in the polyethylene copolymer composition) of a nucleatingagent.

In an embodiment of the disclosure, the polyethylene homopolymercomposition further comprises a nucleating agent which is a salt of adicarboxylic acid compound. A dicarboxylic acid compound is hereindefined as an organic compound containing two carboxyl (—GOOH)functional groups. A salt of a dicarboxylic acid compound then willcomprise one or more suitable cationic counter cations, preferably metalcations, and an organic compound having two anionic carboxylate (—COO⁻)groups.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of molded articles. Such articlesmay be formed by compression molding, continuous compression molding,injection molding or blow molding. Such articles include, for example,caps, screw caps, and closures, including hinged and tethered versionsthereof, for bottles, containers, pouches, pill bottles, fitments,pharmaceutical bottles and the like.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of a fitment for bottles, pouchesor the like.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in flexible packaging.

In an embodiment of the disclosure the polyethylene homopolymercomposition is used in the formation of films, such as for example,blown film, cast film and lamination or extrusion film or extrusioncoating as well as stretch film. Processes to make such films from apolymer are well known to persons skilled in the art.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in an extrusion coating film layer.

In an embodiment of the disclosure the polyethylene homopolymercomposition is used in the formation of one or more than one film layerwhich is part of a multilayer layer film or film structure. Processes tomakes such multilayer films or film structures are well known to personsskilled in the art.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of any closure, of any suitabledesign and dimensions for use in any hot filling process (or asepticfilling process) for filling any suitable bottle, container or the like.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of a closure for bottles,containers, pouches and the like. For example, closures for bottlesformed by continuous compression molding, or injection molding arecontemplated. Such closures include, for example, caps, hinged caps,screw caps, hinged screw caps, snap-top caps, hinged snap-top caps, andoptionally hinged closures for bottles, containers, pouches and thelike.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of a fitment for a pouch, containeror the like.

In an embodiment of the disclosure, the polyethylene homopolymercomposition is used in the formation of molded articles. For example,articles formed by continuous compression molding and injection moldingare contemplated. Such articles include, for example, caps, screw caps,and closures for bottles.

Closures

The terms “cap” and “closure” are used interchangeably in the currentdisclosure, and both connote any suitably shaped molded article forenclosing, sealing, closing or covering etc., a suitably shaped opening,a suitably molded aperture, an open necked structure or the like used incombination with a container, a bottle, a jar, a pouch and the like.

Closures include one piece closures or closures comprising more than onepiece.

In an embodiment of the disclosure, the polyethylene homopolymercompositions described above are used in the formation of a closure.

In an embodiment of the disclosure, the polyethylene homopolymercompositions described above are used in the formation of a one piececlosure.

In an embodiment of the disclosure, the polyethylene homopolymercompositions described above are used in the formation of a closurehaving a tamper evident band (a TEB).

In an embodiment of the disclosure, the polyethylene homopolymercomposition described above are used in the formation of a closure forbottles, containers, pouches and the like. For example, closures forbottles formed by compression molding or injection molding arecontemplated. Such closures include, for example, hinged caps, hingedscrew caps, hinged snap-top caps, and hinged closures for bottles,containers, pouches and the like.

In an embodiment of the disclosure, the polyethylene homopolymercompositions described above are used in the formation of a bottleclosure assembly comprising a cap portion, a tether portion and aretaining means portion.

In an embodiment of the disclosure, a closure (or cap) is a screw capfor a bottle, container, pouch and the like.

In an embodiment of the disclosure, a closure (or cap) is a snap closurefor a bottle, container, pouch and the like.

In an embodiment of the disclosure, a closure (or cap) comprises a hingemade of the same material as the rest of the closure (or cap).

In an embodiment of the disclosure, a closure (or cap) is hingedclosure.

In an embodiment of the disclosure, a closure (or cap) is a hingedclosure for bottles, containers, pouches and the like.

In an embodiment of the disclosure, a closure (or cap) is for retort,hot fill, aseptic fill and cold fill applications.

In an embodiment of the disclosure, a closure (or cap) is a flip-tophinge closure, such as a flip-top hinge closure for use on a plasticketchup bottle or similar containers containing foodstuffs.

When a closure is a hinged closure, it comprises a hinged component andgenerally consists of at least two bodies which are connected by atleast one thinner section that acts as a so called “living hinge”allowing the at least two bodies to bend from an initially moldedposition. The thinner section or sections may be continuous or web-like,wide or narrow.

A useful closure (for bottles, containers and the like) is a hingedclosure and may consist of two bodies joined to each other by at leastone thinner bendable portion (e.g. the two bodies can be joined by asingle bridging portion, or more than one bridging portion, or by awebbed portion, etc.). A first body may contain a dispensing hole andwhich may snap onto or screw onto a container to cover a containeropening (e.g. a bottle opening) while a second body may serve as a snapon lid which may mate with the first body.

The caps and closures, of which hinged caps and closures and screw capsare a subset, can be made according to any known method, including forexample injection molding and compression molding techniques that arewell known to persons skilled in the art. Hence, in an embodiment of thedisclosure a closure (or cap) comprising the polyethylene homopolymercomposition (defined above) is prepared with a process comprising atleast one compression molding step and/or at least one injection moldingstep.

In one embodiment, the caps and closures (including single piece ormulti-piece variants and hinged variants) comprise the polyethylenehomopolymer composition described above which have good barrierproperties, as well as good processability. Hence the closures and capsof this embodiment are well suited for sealing bottles, containers andthe like, for examples bottles that may contain spoilable (for example,due to contact with oxygen) liquids or foodstuffs, including but notlimited to liquids that are under an appropriate pressure (i.e.carbonated beverages or appropriately pressurized drinkable liquids).

The closures and caps may also be used for sealing bottles containingdrinkable water or non-carbonated beverages (e.g. juice). Otherapplications, include caps and closures for bottles, containers andpouches containing foodstuffs, such as for example ketchup bottles andthe like.

The closures and caps may be one-piece closures or two piece closurescomprising a closure and a liner.

The closures and caps may also be of multilayer design, wherein theclosure or cap comprises at least two layers at least one of which ismade of the polyethylene blends described herein.

In an embodiment of the disclosure the closure is made by continuouscompression molding.

In an embodiment of the disclosure the closure is made by injectionmolding.

A closure as described in the present disclosure may be a closuresuitable for use in a container sealing process comprising one of moresteps in which the closure comes into contact with a liquid at elevatedtemperatures, such as a hot fill processes, and in some cases an asepticfill processes. Such closures and processes are described in for exampleCA Pat. Appl. Nos 2,914,353; 2,914,354; and 2,914,315.

In an embodiment of the disclosure, a closure made is a PCO 1881 CSDclosure, having a weight of about 2.15 grams and having the followingdimensions: Closure height (not including Tamper Ring)=about 10.7 mm;Closure height with Tamper Ring=about 15.4 mm; Outside diameter @ 4mm=about 29.6 mm; Thread diameter=about 25.5 mm; Bump sealdiameter=about 24.5 mm; Bump seal thickness=about 0.7 mm; Bump sealheight to center of olive=about 1.5 mm; Bore seal diameter=about 22.5mm; Bore seal thickness=about 0.9 mm; Bore height to center ofolive=about 1.6 mm; Top panel thickness=about 1.2 mm; Tamper bandundercut diameter=about 26.3 mm; Thread depth=about 1.1 mm; Threadpitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In an embodiment of the disclosure, a closure is made using an injectionmolding process to prepare a PCO 1881 CSD closure, having a weight ofabout 2.15 grams and having the following dimensions: Closure height(not including Tamper Ring)=about 10.7 mm; Closure height with TamperRing=about 15.4 mm; Outside diameter @ 4 mm=about 29.6 mm; Threaddiameter=about 25.5 mm; Bump seal diameter=about 24.5 mm; Bump sealthickness=about 0.7 mm; Bump seal height to center of olive=about 1.5mm; Bore seal diameter=about 22.5 mm; Bore seal thickness=about 0.9 mm;Bore height to center of olive=about 1.6 mm; Top panel thickness=about1.2 mm; Tamper band undercut diameter=about 26.3 mm; Thread depth=about1.1 mm; Thread pitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure, having aweight of about 2.15 grams and having the following dimensions: Closureheight (not including Tamper Ring)=about 10.7 mm; Closure height withTamper Ring=about 15.4 mm; Outside diameter @ 4 mm=about 29.6 mm; Threaddiameter=about 25.5 mm; Bump seal diameter=about 24.5 mm; Bump sealthickness=about 0.7 mm; Bump seal height to center of olive=about 1.5mm; Bore seal diameter=about 22.5 mm; Bore seal thickness=about 0.9 mm;Bore height to center of olive=about 1.6 mm; Top panel thickness=about1.2 mm; Tamper band undercut diameter=about 26.3 mm; Thread depth=about1.1 mm; Thread pitch=about 2.5 mm; Thread Root @ 4 mm=27.4 mm.

In embodiments of the disclosure, a closure is made using a moldingprocess to prepare a PCO 1881 CSD closure having a having an oxygentransmission rate, OTR of ≤0.0030 cm³/closure/day, or ≤0.0025cm³/closure/day, or ≤0.0021 cm³/closure/day, or ≤0.0020 cm³/closure/day,s 0.0018 cm³/closure/day, or ≤0.0016 cm³/closure/day, or ≤0.0014cm³/closure/day.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of ≤0.0030 cm³/closure/day, or ≤0.0025cm³/closure/day, or ≤0.0021 cm³/closure/day, or ≤0.0020 cm³/closure/day,≤0.0018 cm³/closure/day, or ≤0.0016 cm³/closure/day, or 0.0014cm³/closure/day.

In an embodiment of the disclosure, the closure is made using aninjection molding process to prepare a PCO 1881 CSD closure having ahaving an oxygen transmission rate, OTR of ≤0.0030 cm³/closure/day, or≤0.0025 cm³/closure/day, or ≤0.0021 cm³/closure/day, or ≤0.0020cm³/closure/day, ≤0.0018 cm³/closure/day, or ≤0.0016 cm³/closure/day, or≤0.0014 cm³/closure/day.

In embodiments of the disclosure, a closure is made using a moldingprocess to prepare a PCO 1881 CSD closure having an oxygen transmissionrate, OTR of from 0.0005 to 0.0025 cm³/closure/day including anynarrower ranges within this range and any values encompassed by theseranges. For example, in embodiments of the disclosure, a closure is madeusing a molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of from 0.0006 to 0.0023 cm³/closure/day,or from 0.0006 to 0.0021 cm³/closure/day, or from 0.0006 to 0.0019cm³/closure/day, or from 0.0006 to 0.0017 cm³/closure/day, or from0.0006 to 0.0015 cm³/closure/day, or from 0.0006 to 0.0013cm³/closure/day.

In an embodiment of the disclosure, a closure is made using a continuouscompression molding process to prepare a PCO 1881 CSD closure having anoxygen transmission rate, OTR of from 0.0005 to 0.0025 cm³/closure/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a closure is made using a continuous compression moldingprocess to prepare a PCO 1881 CSD closure having an oxygen transmissionrate, OTR of from 0.0006 to 0.0023 cm³/closure/day, or from 0.0006 to0.0021 cm³/closure/day, or from 0.0006 to 0.0019 cm³/closure/day, orfrom 0.0006 to 0.0017 cm³/closure/day, or from 0.0006 to 0.0015cm³/closure/day, or from 0.0006 to 0.0013 cm³/closure/day.

In an embodiment of the disclosure, a closure is made using an injectionmolding process to prepare a PCO 1881 CSD closure having a having anoxygen transmission rate, OTR of from 0.0005 to 0.0025 cm³/closure/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a closure is made using an injection molding process toprepare a PCO 1881 CSD closure having a having an oxygen transmissionrate, OTR of from 0.0006 to 0.0023 cm³/closure/day, or from 0.0006 to0.0021 cm³/closure/day, or from 0.0006 to 0.0019 cm³/closure/day, orfrom 0.0006 to 0.0017 cm³/closure/day, or from 0.0006 to 0.0015cm³/closure/day, or from 0.0006 to 0.0013 cm³/closure/day.

Cast (and Lamination) Film

In an embodiment of the disclosure, the polyethylene homopolymercompositions described above are used in the formation of a cast film orlaminate film.

Cast films are extruded from a flat die onto a chilled roll or a nippedroll, optionally, with a vacuum box and/or air-knife. The films may bemonolayer or coextruded multi-layer films obtained by various extrusionthrough a single or multiple dies. The resultant films may be the usedas-is or may be laminated to other films or substrates, for example bythermal, adhesive lamination or direct extrusion onto a substrate. Theresultant films and laminates may be subjected to other formingoperations such as embossing, stretching, thermoforming. Surfacetreatments such as corona may be applied and the films may be printed.

In the cast film extrusion process, a thin film is extruded through aslit onto a chilled, highly polished turning roll, where it is quenchedfrom one side. The speed of the roller controls the draw ratio and finalfilm thickness. The film is then sent to a second roller for cooling onthe other side. Finally, it passes through a system of rollers and iswound onto a roll. In another embodiment, two or more thin films arecoextruded through two or more slits onto a chilled, highly polishedturning roll, the coextruded film is quenched from one side. The speedof the roller controls the draw ratio and final coextruded filmthickness. The coextruded film is then sent to a second roller forcooling on the other side. Finally, it passes through a system ofrollers and is wound onto a roll.

In an embodiment, the cast film product may further be laminated one ormore layers into a multilayer structure.

The cast films and laminates may be used in a variety of purposes, forexample food packaging (dry foods, fresh foods, frozen foods, liquids,processed foods, powders, granules), for packaging of detergents,toothpaste, towels, for labels and release liners. The films may also beused in unitization and industrial packaging, notably in stretch films.The films may also be used in hygiene and medical applications, forexample in breathable and non-breathable films used in diapers, adultincontinence products, feminine hygiene products, ostomy bags. Finally,cast films may also be used in tapes and artificial turf applications.

In embodiments of the disclosure, a film or film layer has a normalizedoxygen transmission rate, OTR of ≤100 cm³/100 in²/day, or ≤90 cm³/100in²/day, or ≤80 cm³/100 in²/day, or ≤70 cm³/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized oxygen transmission rate, OTR of ≤100 cm³/100in²/day, or ≤90 cm³/100 in²/day, or ≤80 cm³/100 in²/day, or ≤70 cm³/100in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized oxygen transmission rate, OTR of ≤100 cm³/100 in²/day, or 90cm³/100 in²/day, or ≤80 cm³/100 in²/day, or ≤70 cm³/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized oxygen transmission rate, OTR of ≤100 cm³/100 in²/day, or 90cm³/100 in²/day, or ≤80 cm³/100 in²/day, or ≤70 cm³/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedoxygen transmission rate, OTR of from 30 to 100 cm³/100 in²/day,including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a film or film layer has a normalized oxygen transmissionrate, OTR of from 30 to 90 cm³/100 in²/day, or from 40 to 90 cm³/100in²/day, or from 30 to 80 cm³/100 in²/day, or from 40 to 80 cm³/100in²/day, or from 30 to 70 cm³/100 in²/day, or from 40 to 70 cm³/100in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized oxygen transmission rate, OTR of from 30 to 100cm³/100 in²/day, including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a compression molded film or film layer has a normalizedoxygen transmission rate, OTR of from 30 to 90 cm³/100 in²/day, or from40 to 90 cm³/100 in²/day, or from 30 to 80 cm³/100 in²/day, or from 40to 80 cm³/100 in²/day, or from 30 to 70 cm³/100 in²/day, or from 40 to70 cm³/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized oxygen transmission rate, OTR of from 30 to 100 cm³/100in²/day, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a cast film or film layer has a normalized oxygentransmission rate, OTR of from 30 to 90 cm³/100 in²/day, or from 40 to90 cm³/100 in²/day, or from 30 to 80 cm³/100 in²/day, or from 40 to 80cm³/100 in²/day, or from 30 to 70 cm³/100 in²/day, or from 40 to 70cm³/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized oxygen transmission rate, OTR of from 30 to 100 cm³/100in²/day, including any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a lamination film or film layer has a normalized oxygentransmission rate, OTR of from 30 to 90 cm³/100 in²/day, or from 40 to90 cm³/100 in²/day, or from 30 to 80 cm³/100 in²/day, or from 40 to 80cm³/100 in²/day, or from 30 to 70 cm³/100 in²/day, or from 40 to 70cm³/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedwater vapor transmission rate, W/TR of ≤0.250 g/100 in²/day, or ≤0.230g/100 in²/day, or ≤0.210 g/100 in²/day, or ≤0.200 g/100 in²/day, or≤0.190 g/100 in²/day, or s 0.180 g/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized water vapor transmission rate, WVTR of ≥0.250g/100 in²/day, or ≥0.230 g/100 in²/day, or ≤0.210 g/100 in²/day, or≥0.200 g/100 in²/day, or ≥0.190 g/100 in²/day, or ≥0.180 g/100 in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized water vapor transmission rate, W/TR of ≤0.250 g/100 in²/day,or ≤0.230 g/100 in²/day, or ≤0.210 g/100 in²/day, or ≤0.200 g/100in²/day, or ≤0.190 g/100 in²/day, or ≤0.180 g/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized water vapor transmission rate, W/TR of ≤0.250 g/100 in²/day,or ≤0.230 g/100 in²/day, or ≤0.210 g/100 in²/day, or ≤0.200 g/100in²/day, or ≤0.190 g/100 in²/day, or ≤0.180 g/100 in²/day.

In embodiments of the disclosure, a film or film layer has a normalizedwater vapor transmission rate, VWTR of from 0.080 to 0.250 g/100 in²/dayincluding any narrower ranges within this range and any valuesencompassed by these ranges. For example, in embodiments of thedisclosure, a film or film layer has a normalized water vaportransmission rate, VWTR of from 0.100 to 0.230 g/100 in²/day, or from0.100 to 0.210 g/100 in²/day, or from 0.100 to 0.200 g/100 in²/day, orfrom 0.100 to 0.190 g/100 in²/day, or from 0.100 to 0.180 g/100 in²/day,or from 0.100 to 0.175 g/100 in²/day, or from 0.110 to 0.230 g/100in²/day, or from 0.110 to 0.210 g/100 in²/day, or from 0.110 to 0.200g/100 in²/day, or from 0.110 to 0.190 g/100 in²/day, or from 0.110 to0.180 g/100 in²/day, or from 0.110 to 0.175 g/100 in²/day.

In embodiments of the disclosure, a compression molded film or filmlayer has a normalized water vapor transmission rate, W/TR of from 0.080to 0.250 g/100 in²/day including any narrower ranges within this rangeand any values encompassed by these ranges. For example, in embodimentsof the disclosure, a compression molded film or film layer has anormalized water vapor transmission rate, VWTR of from 0.100 to 0.230g/100 in²/day, or from 0.100 to 0.210 g/100 in²/day, or from 0.100 to0.200 g/100 in²/day, or from 0.100 to 0.190 g/100 in²/day, or from 0.100to 0.180 g/100 in²/day, or from 0.100 to 0.175 g/100 in²/day, or from0.110 to 0.230 g/100 in²/day, or from 0.110 to 0.210 g/100 in²/day, orfrom 0.110 to 0.200 g/100 in²/day, or from 0.110 to 0.190 g/100 in²/day,or from 0.110 to 0.180 g/100 in²/day, or from 0.110 to 0.175 g/100in²/day.

In embodiments of the disclosure, a cast film or film layer has anormalized water vapor transmission rate, VWTR of from 0.080 to 0.250g/100 in²/day including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a cast film or film layer has a normalized water vaportransmission rate, VWTR of from 0.100 to 0.230 g/100 in²/day, or from0.100 to 0.210 g/100 in²/day, or from 0.100 to 0.200 g/100 in²/day, orfrom 0.100 to 0.190 g/100 in²/day, or from 0.100 to 0.180 g/100 in²/day,or from 0.100 to 0.175 g/100 in²/day, or from 0.110 to 0.230 g/100in²/day, or from 0.110 to 0.210 g/100 in²/day, or from 0.110 to 0.200g/100 in²/day, or from 0.110 to 0.190 g/100 in²/day, or from 0.110 to0.180 g/100 in²/day, or from 0.110 to 0.175 g/100 in²/day.

In embodiments of the disclosure, a lamination film or film layer has anormalized water vapor transmission rate, VWTR of from 0.080 to 0.250g/100 in²/day including any narrower ranges within this range and anyvalues encompassed by these ranges. For example, in embodiments of thedisclosure, a lamination film or film layer has a normalized water vaportransmission rate, VWTR of from 0.100 to 0.230 g/100 in²/day, or from0.100 to 0.210 g/100 in²/day, or from 0.100 to 0.200 g/100 in²/day, orfrom 0.100 to 0.190 g/100 in²/day, or from 0.100 to 0.180 g/100 in²/day,or from 0.100 to 0.175 g/100 in²/day, or from 0.110 to 0.230 g/100in²/day, or from 0.110 to 0.210 g/100 in²/day, or from 0.110 to 0.200g/100 in²/day, or from 0.110 to 0.190 g/100 in²/day, or from 0.110 to0.180 g/100 in²/day, or from 0.110 to 0.175 g/100 in²/day.

Further non-limiting details of the disclosure are provided in thefollowing examples. The examples are presented for the purposes ofillustrating selected embodiments of this disclosure, it beingunderstood that the examples presented do not limit the claimspresented.

EXAMPLES General Polymer Characterization Methods

Prior to testing, each specimen was conditioned for at least 24 hours at23±2° C. and 50±10% relative humidity and subsequent testing wasconducted at 23±2° C. and 50±10% relative humidity. Herein, the term“ASTM conditions” refers to a laboratory that is maintained at 23±2° C.and 50±10% relative humidity; and specimens to be tested wereconditioned for at least 24 hours in this laboratory prior to testing.ASTM refers to the American Society for Testing and Materials.

Polyethylene homopolymer composition density (in g/cm³) was determinedusing ASTM D792-13 (Nov. 1, 2013).

Melt index was determined using ASTM D1238 (Aug. 1, 2013). Melt indexes,I₂, I₆, I₁₀ and I₂₁ were measured at 190° C., using weights of 2.16 kg,6.48 kg, 10 kg and a 21.6 kg respectively. Herein, the term “stressexponent” or its acronym “S.Ex.”, is defined by the followingrelationship: S.Ex.=log (I₆/I₂)/log(6480/2160); wherein I₆ and I₂ arethe melt flow rates measured at 190° C. using 6.48 kg and 2.16 kg loads,respectively.

M_(n), M_(w), and M_(z)(g/mol) were determined by high temperature GelPermeation Chromatography (GPC) with differential refractive index (DRI)detection using universal calibration (e.g. ASTM-D6474-99). GPC data wasobtained using an instrument sold under the trade name “Waters 150c”,with 1,2,4-trichlorobenzene as the mobile phase at 140° C. The sampleswere prepared by dissolving the polymer in this solvent and were runwithout filtration. Molecular weights are expressed as polyethyleneequivalents with a relative standard deviation of 2.9% for the numberaverage molecular weight (“Mn”) and 5.0% for the weight averagemolecular weight (“Mw”). The molecular weight distribution (MWD) is theweight average molecular weight divided by the number average molecularweight, M_(w)/M_(n). The z-average molecular weight distribution isM_(z)/M_(n). Polymer sample solutions (1 to 2 mg/mL) were prepared byheating the polymer in 1,2,4-trichlorobenzene (TCB) and rotating on awheel for 4 hours at 150° C. in an oven. The antioxidant2,6-di-tert-butyl-4-methylphenol (BHT) was added to the mixture in orderto stabilize the polymer against oxidative degradation. The BHTconcentration was 250 ppm. Sample solutions were chromatographed at 140°C. on a PL 220 high-temperature chromatography unit equipped with fourSHODEX® columns (HT803, HT804, HT805 and HT806) using TCB as the mobilephase with a flow rate of 1.0 mL/minute, with a differential refractiveindex (DRI) as the concentration detector. BHT was added to the mobilephase at a concentration of 250 ppm to protect the columns fromoxidative degradation. The sample injection volume was 200 mL. The rawdata were processed with CIRRUS® GPC software. The columns werecalibrated with narrow distribution polystyrene standards. Thepolystyrene molecular weights were converted to polyethylene molecularweights using the Mark-Houwink equation, as described in the ASTMstandard test method D6474.

Primary melting peak (° C.), heat of fusion (J/g) and crystallinity (%)was determined using differential scanning calorimetry (DSC) as follows:the instrument was first calibrated with indium; after the calibration,a polymer specimen is equilibrated at 0° C. and then the temperature wasincreased to 200° C. at a heating rate of 10° C./min; the melt was thenkept isothermally at 200° C. for five minutes; the melt was then cooledto 0° C. at a cooling rate of 10° C./min and kept at 0° C. for fiveminutes; the specimen was then heated to 200° C. at a heating rate of10° C./min. The DSC Tm, heat of fusion and crystallinity are reportedfrom the 2^(nd) heating cycle.

Unsaturations in the polyethylene homopolymer composition weredetermined by Fourier Transform Infrared Spectroscopy (FTIR) as per ASTMD3124-98.

Hexane extractables were determined according to ASTM D5227.

Shear viscosity was measured by using a Kayeness WinKARS CapillaryRheometer (model #D5052M-115). For the shear viscosity at lower shearrates, a die having a die diameter of 0.06 inch and L/D ratio of 20 andan entrance angle of 180 degrees was used. For the shear viscosity athigher shear rates, a die having a die diameter of 0.012 inch and L/Dratio of 20 was used.

The Shear Viscosity Ratio as the term is used in the present disclosureis defined as: η₁₀₀/η₁₀₀₀₀₀ at 240° C. The processability indicator isdefined as 100/η₁₀₀₀₀₀. The η₁₀₀ is the melt shear viscosity at theshear rate of 100 s⁻¹ and the η₁₀₀₀₀₀ is the melt shear viscosity at theshear rate of 100000 s⁻¹ measured at 240° C.

The “processability indicator” as used herein is defined as:processability Indicator=100/η(10⁵ s⁻¹, 240° C.); where q is the shearviscosity measured at 10⁵ 1/s at 240° C.

Dynamic mechanical analyses were carried out with a rheometer, namelyRheometrics Dynamic Spectrometer (RDS-II) or Rheometrics SR5 or ATSStresstech, on compression molded samples under nitrogen atmosphere at190° C., using 25 mm diameter cone and plate geometry. The oscillatoryshear experiments were done within the linear viscoelastic range ofstrain (10% strain) at frequencies from 0.05 to 100 rad/s. The values ofstorage modulus (G′), loss modulus (G″), complex modulus (G*) andcomplex viscosity (η*) were obtained as a function of frequency. Thesame rheological data can also be obtained by using a 25 mm diameterparallel plate geometry at 190° under nitrogen atmosphere. The Zeroshear viscosity is estimated using the Ellis model, i.e.η(ω)=η₀/(1+−τ/Σ_(1/2))^(α-1), where η₀ is the zero shear viscosity.T_(1/2) is the value of the shear stress at which η=η₀/2 and α is one ofthe adjustable parameters. The Cox-Merz rule is assumed to be applicablein the present disclosure. The SHI(1,100) value is calculated accordingto the methods described in WO 2006/048253 and WO 2006/048254.

The DRI, is the “dow rheology index”, and is defined by the equation:DRI=[³⁶5000(τ₀/η₀)−1]/10; wherein τ₀ is the characteristic relaxationtime of the polyethylene and η₀ is the zero shear viscosity of thematerial. The DRI is calculated by least squares fit of the rheologicalcurve (dynamic complex viscosity versus applied frequency e.g. 0.01-100rads/s) as described in U.S. Pat. No. 6,114,486 with the followinggeneralized Cross equation, i.e. η(ω)=η₀/[1+(ωΣ₀)^(n)]; wherein n is thepower law index of the material, η(ω) and ω are the measured complexviscosity and applied frequency data respectively. When determining theDRI, the zero shear viscosity, no used was estimated with the Ellismodel, rather than the Cross model.

The crossover frequency is the frequency at which storage modulus (G′)and loss modulus (G″) curves cross with each other, while G′@G″=500 Pais the storage modulus at which the loss modulus (G″) is at 500 Pa.

Plaques molded from the polyethylene homopolymer compositions weretested according to the following ASTM methods: Bent Strip EnvironmentalStress Crack Resistance (ESCR) at Condition B at 100% IGEPAL at 50° C.,ASTM D1693; notched Izod impact properties, ASTM D256; FlexuralProperties, ASTM D 790; Tensile properties, ASTM D 638; Vicat softeningpoint, ASTM D 1525; Heat deflection temperature, ASTM D 648.

Examples of the polyethylene homopolymer compositions were produced in adual reactor solution polymerization process in which the contents ofthe first reactor flow into the second reactor. This in-series “dualreactor” process produces an “in-situ” polyethylene blend (i.e., thepolyethylene homopolymer composition). Note, that when an in-seriesreactor configuration is used, un-reacted ethylene monomer present inthe first reactor, will flow into the downstream second reactor forfurther polymerization.

In the present inventive examples, no co-monomer is fed to the first orsecond reactors, and an ethylene homopolymer is formed in each reactor.Each reactor is sufficiently agitated to give conditions in whichcomponents are well mixed. The volume of the first reactor was 12 litersand the volume of the second reactor was 22 liters. These are the pilotplant scales. The first reactor was operated at a pressure of 10500 to35000 kPa and the second reactor was operated at a lower pressure tofacilitate continuous flow from the first reactor to the second. Thesolvent employed was methylpentane. The process operates usingcontinuous feed streams. The catalyst employed in the dual reactorsolution process experiments was a phosphinimine catalyst, which was atitanium complex having a phosphinimine ligand ((tert-butyl)₃P=N), acyclopentadienide ligand (Cp) and two activatable ligands (chlorideligands; note: “activatable ligands” are removed, by for exampleelectrophilic abstraction using a co-catalyst or activator to generatean active metal center). A boron based co-catalyst (Ph₃CB(C₆F₅)₄) wasused in approximately stoichiometric amounts relative to the titaniumcomplex. Commercially available methylaluminoxane (MAO) was included asa scavenger at an Al:Ti of about 40:1. In addition,2,6-di-tert-butylhydroxy-4-ethylbenzene was added to scavenge freetrimethylaluminum within the MAO in a ratio of Al:OH of about 0.5:1. Thepolymerization conditions used to make the inventive polyethylenehomopolymer compositions are provided in Table 1.

The polyethylene homopolymer compositions of Examples 1 and 2 which areinventive are made using a single site phosphinimine catalyst in a dualreactor solution process as described above. Each has a weight averagemolecular weight, M_(w) of below about 65,000 g/mol and a melt index, I₂of greater than 10 g/10 min.

Comparative polyethylene homopolymer compositions (Examples 3 and 4),which were nucleated with HPN20E (which can be obtained commerciallyfrom Milliken Chemical) in the same manner and to the same amountsExamples 1 and 2 (see below), were prepared in a dual reactor solutionpolymerization process using a phosphinimine catalyst, in a mannersubstantially as outlined in U.S. Pat. Pub. Nos. 2008/0118749 and2015/0203671 both of which are incorporated herein in their entirety.

The comparative polyethylene homopolymer compositions of Example 3 and 4each has a melt index, I₂ of less 10 g/10 min and a weight averagemolecular weight, M_(w) of greater than about 65,000 g/mol.

As can be seen in FIG. 1, the inventive Examples 1 and 2 have a bimodalmolecular weight distribution or profile in a GPC analysis, as do thecomparative Examples 3 and 4.

Non-nucleated and nucleated Inventive and as well Comparativepolyethylene homopolymer composition properties are provided in Table 2.The nucleated Inventive resins which are denoted in the Tables with thesymbol were prepared in the following manner. A 4% (by weight)masterbatch of HYPERFORM® HPN-20E nucleating agent from MillikenChemical was first prepared. This masterbatch also contained 1% (byweight) of DHT-4V (aluminium magnesium carbonate hydroxide) from KisumaChemicals. The base resin and the nucleating agent masterbatch were thenmelt blended using a Coperion ZSK 26 co-rotating twin screw extruderwith an L/D of 32:1 to give a polyethylene homopolymer compositionhaving 1200 parts per million (ppm) of the HYPERFORM HPN-20E nucleatingagent present (based on the weight of the polyethylene homopolymercomposition). The extruder was fitted with an underwater pelletizer anda Gala spin dryer. The materials were co-fed to the extruder usinggravimetric feeders to achieve the desired nucleating agent level. Theblends were compounded using a screw speed of 200 rpm at an output rateof 15-20 kg/hour and at a melt temperature of 225-230° C.

The calculated properties for the first ethylene homopolymer and thesecond ethylene homopolymer present in each of the inventive andcomparative homopolymer compositions are provided in Table 3 (see“Polymerization Reactor Modeling” below for methods of calculating theseproperties).

The properties of pressed plaques made from non-nucleated and nucleatedinventive polyethylene homopolymer compositions as well as comparativecompositions are provided in Table 4.

Polymerization Reactor Modeling

For multicomponent (or bimodal resins) polyethylene polymers with verylow comonomer content, it can be difficult to reliably estimate theshort chain branching (and subsequently polyethylene resin density bycombining other information) of each polymer component by mathematicaldeconvolution of GPC-FTIR data, as was done in for example U.S. Pat. No.8,022,143. Instead, the M_(w), M_(n), M_(z), M_(w)/M_(n) of the firstand second ethylene homopolymers were calculated herein using thePolymerization Reactor Modeling that was described in detail in U.S.Pat. No. 9,074,082, but with the exception that the short chainbranching per thousand carbons (SCB/1000C) of each of the first andsecond polymer components, the first and second ethylene homopolymerswas set to zero due to absence of comonomer in the feed. ThePolymerization reactor model or simulation used the input conditionswhich were employed for actual pilot scale run conditions (forreferences on relevant reactor modeling methods, see “Copolymerization”by A. Hamielec, J. MacGregor, and A. Penlidis in Comprehensive PolymerScience and Supplements, volume 3, Chapter 2, page 17, Elsevier, 1996and “Copolymerization of Olefins in a Series of Continuous Stirred-TankSlurry-Reactors using Heterogeneous Ziegler-Natta and MetalloceneCatalysts. I. General Dynamic Mathemacial Model” by J. B. P Soares andA. E Hamielec in Polymer Reaction Engineering, 4(2&3), p153, 1996.)

The model takes for input the flow of several reactive species (e.g.catalyst, monomer such as ethylene, hydrogen, and solvent) going to eachreactor, the temperature (in each reactor), and the conversion ofethylene (in each reactor), and calculates the polymer properties (ofthe polymer made in each reactor, i.e. the first and second ethylenehomopolymers) using a terminal kinetic model for continuously stirredtank reactors (CSTRs) connected in series. The “terminal kinetic model”assumes that the kinetics depend upon the monomer (e.g. ethylene) unitwithin the polymer chain on which the active catalyst site is located(see “Copolymerization” by A. Hamielec, J. MacGregor, and A. Penlidis inComprehensive Polymer Science and Supplements, volume 3, Chapter 2, page17, Elsevier, 1996). In the model, the homopolymer chains are assumed tobe of reasonably large molecular weight to ensure that the statistics ofmonomer unit insertion at the active catalyst center is valid and thatmonomers consumed in routes other than propagation are negligible. Thisis known as the “long chain” approximation.

The terminal kinetic model for polymerization includes reaction rateequations for activation, initiation, propagation, chain transfer, anddeactivation pathways. This model solves the steady-state conservationequations (e.g. the total mass balance and heat balance) for thereactive fluid which comprises the reactive species identified above.

The total mass balance for a generic CSTR with a given number of inletsand outlets is given by:

0=Σ_(i) {dot over (m)} _(i)  (1)

where {dot over (m)}_(i) represents the mass flow rate of individualstreams with index i indicating the inlet and outlet streams.

Equation (1) can be further expanded to show the individual species andreactions:

$\begin{matrix}{0 = {\frac{\sum_{i}^{m{\overset{.}{x}}_{ij}}{/M_{i}}}{\rho_{mix}V} + {R_{j}/\rho_{mix}}}} & (2)\end{matrix}$

where M_(i) is the average molar weight of the fluid inlet or outlet(i), x_(ij) is the mass fraction of species j in stream i, ρ_(mix) isthe molar density of the reactor mixture, V is the reactor volume, R_(j)is the reaction rate for species j, which has units of kmol/m³ s.

The total heat balance is solved for an adiabatic reactor and is givenby:

0=(Σ{dot over (m)} _(i) ΔH _(i) +q _(Rx) V+{dot over (W)}−{dot over(Q)})  (3)

where, {dot over (m)}_(i) is the mass flow rate of stream i (inlet oroutlet), ΔH_(i) is the difference in enthalpy of stream i versus areference state, q_(Rx) is the heat released by reaction(s), V is thereactor volume, {dot over (W)} is the work input (i.e. agitator), {dotover (Q)} is the heat input/loss.

The catalyst concentration input to each reactor is adjusted to matchthe experimentally determined ethylene conversion and reactortemperature values in order solve the equations of the kinetic model(e.g. propagation rates, heat balance and mass balance).

The H₂ concentration input to each reactor may be likewise adjusted sothat the calculated molecular weight distribution of a polymer made overboth reactors (and hence the molecular weight of polymer made in eachreactor) matches that which is observed experimentally.

The degree of polymerization (DPN) for a homopolymerization reaction isgiven by the ratio of the rate of chain propagation reactions over therate of chain transfer/termination reactions:

$\begin{matrix}{{D\; P\; N} = \frac{k_{p11}\left\lbrack m_{1} \right\rbrack}{{k_{tm11}\left\lbrack m_{1} \right\rbrack} + k_{ts1} + {k_{tH1}\lbrack H\rbrack}}} & (4)\end{matrix}$

where k_(p11) is the propagation rate constant for monomer 1, [m₁] isthe molar concentration of monomer 1 (ethylene) in the reactor, k_(tm11)the termination rate constant for chain transfer to monomer, k_(ts1) israte constant for the spontaneous chain termination for a chain endingwith monomer 1, k_(tH1) is the rate constant for the chain terminationby hydrogen for a chain ending with monomer 1.

The number average molecular weight (Mn) for a polymer follows from thedegree of polymerization and the molecular weight of a monomer unit.From the number average molecular weight of polymer in each reactor, andassuming a Flory distribution for a single site catalyst, the molecularweight distribution is determined for the polymer formed in eachreactor:

w(n)=τ² ne ^(−τn)  (5)

where

$\tau = \frac{1}{D\; P\; N}$

and w(n) is the weight fraction of polymer having a chain length n. TheFlory distribution can be transformed into the common log scaled GPCtrace by applying.

$\begin{matrix}{\frac{dW}{d\;{\log(M)}} = {{\ln\left( {10} \right)}\frac{n^{2}}{D\; P\; N^{2}}e^{({- \frac{n}{D\; P\; N}})}}} & (6)\end{matrix}$

where

$\frac{dW}{d\;{\log({MW})}}$

is the differential weight fraction of polymer with a chain length n(n=MW/28 where 28 is the molecular weight of the polymer segmentcorresponding to a C₂H₄ unit) and DPN is the degree of polymerization ascalculated by Equation (4). From the Flory model, the M_(w) and theM_(z) of the polymer made in each reactor are: M_(w)=2×M_(n) andM_(z)=1.5×M_(w).

The overall molecular weight distribution over both reactors is simplythe sum of the molecular weight distribution of polymer made in eachreactor, and where each Flory distribution is multiplied by the weightfraction of polymer made in each reactor:

$\begin{matrix}{\frac{d\overset{\_}{W}}{d\;{\log\left( {MW} \right)}} = {{W_{R1}\left( {{\ln\left( {10} \right)}\frac{n^{2}}{{DP}N_{R1}^{2}}e^{({- \frac{n}{D\; P\; N_{R1}}})}} \right)} + {W_{R2}\left( {\ln\left( {10} \right)\frac{n^{2}}{{DP}N_{R\; 2}^{2}}e^{({- \frac{n}{D\; P\; N_{R\; 2}}})}} \right)}}} & (10)\end{matrix}$

where dW/dlog(MW) is the overall molecular weight distribution function,w_(R1) and w_(R2) are the weight fraction of polymer made in eachreactor, DPN₁ and DPN₂ is the average chain length of the polymer madein each reactor (i.e. DPN₁=M_(nR1)/28. The weight fraction of materialmade in each reactor is determined from knowing the mass flow of monomerinto each reactor along with knowing the conversions for monomer in eachreactor.

The moments of the overall molecular weight distribution (or themolecular weight distribution of polymer made in each reactor) can becalculated using equations 8a, 8b and 8c (a Flory Model is assumedabove, but the below generic formula apply to other model distributionsas well):

$\begin{matrix}{\overset{\_}{M_{n}} = \frac{\sum_{i}w_{i}}{\sum_{i}\frac{w_{i}}{\;_{M_{i}}}}} & \left( {8a} \right) \\{\overset{\_}{M_{w}} = \frac{\sum_{i}{w_{i}M_{i}}}{\sum_{i}w_{i}}} & \left( {8b} \right) \\{\overset{\_}{M_{Z}} = \frac{\sum_{i}{w_{i}M_{i}^{2}}}{\sum_{i}{w_{i}M_{i}}}} & \left( {8c} \right)\end{matrix}$

For the polymer obtained in each reactor, the key resin parameters whichare obtained from the above described kinetic model are the molecularweights Mn, Mw and Mz, the molecular weight distributions M_(w)/M_(n)and Mz/Mw the branching frequency (in this case 0). With thisinformation in hand, a component (or composition) density model and acomponent (or composition) melt index, 12, model was used according tothe following equations, which were empirically determined, to calculatethe density and melt index 12 of each of the first and second ethylenehomopolymers:

Density:

$\frac{1}{\rho} = {{{1.0}142} + {{0.0}033\left( {1{{.22} \cdot {BF}}} \right)^{{0.8}346}} + \frac{{0.0}303k^{{0.9}804}}{1 + \frac{0.3712}{e^{{1.2}2BF}}}}$

where, BF is the branching frequency (note that here, the BF=0, as isappropriate for a homopolymer),

k = Log₁₀(M_(n)/1000)

Melt Index, I₂ (MI):

${Lo{g_{10}({MI})}} = {{{7.8}998} - {{3.9}089Lo{g_{10}\left( \frac{M_{w}}{1000} \right)}} - {{0.2}799\frac{M_{n}}{M_{w}}}}$

Hence, the above models were used to estimate the branch frequency,weight fraction (or weight percent), melt index and the density of thepolyethylene composition components, which were formed in each ofreactor 1 and 2 (i.e. the first and second ethylene homopolymers).

TABLE 1 Reactor Conditions Example No. Inv. 1 Inv. 2 Reactor 1 Ethylene(kg/h) 36 36 Octene (kg/h) 0 0 Hydrogen (g/h) 1.1 1.4 Solvent (kg/h) 307307 Reactor feed inlet temperature (° C.) 35 35 Reactor Temperature (°C.) 162.9 163 Titanium Catalyst (ppm) 0.0174 0.0140 Reactor 2 Ethylene(kg/h) 36.1 36 Octene (kg/h) 0 0 Hydrogen (g/h) 27 28 Solvent (kg/h)170.9 170.9 Reactor feed inlet temperature (° C.) 35 35 ReactorTemperature (° C.) 199.9 190.2 Titanium Catalyst (ppm) 0.0547 0.0583

TABLE 2 Resin Properties Example No. Inv. 1 Inv. 1* Inv. 2 Inv. 2* Comp.3 Comp. 4 Nucleating Agent None HPN20E None HPN20E HPN20E HPN20E Density(g/cm³) 0.9662 0.9684 0.9675 0.9698 0.966 0.968 Base Resin Density(g/cm³) 0.9662 0.9675 density increase after 0.0022 0.0023 nucleationMelt Index I₂ (g/10 min), 12.2 20.4 1.2 6 base resin Melt Index I₆ (g/10min) 49.2 81.6 5.49 24.5 Melt Index I₁₀ (g/10 min) 86.9 155 11 45.5 MeltIndex I₂₁ (g/10 min) 403 661 69 194 Melt Flow Ratio (I₂₁/I₂) 33.2 32.557 33 Stress Exponent 1.27 1.26 1.38 1.27 Melt Flow Ratio (I₁₀/I₂) 7.647.62 9.4 7.59 Rheological Properties Shear viscosity (η) at 10⁵ 4.4 4.05.4 5.2 s⁻¹ (240° C., Pa-s) 100/η at 10⁵ s⁻¹ (240° C.), 22.7 25 18.519.2 Processability Indicator Shear viscosity Ratio η₁₀₀/ 62 42.6 185 87η₁₀₀₀₀₀ (240° C.) Zero Shear Viscosity- 769.5 413.54 190° C. (Pa-s) DRI0.262 0.24 G′@G″ = 500 Pa 21.1 15 DSC Primary Melting Peak (° C.) 131.69133.93 131.77 134.39 133.74 133.80 Heat of Fusion (J/g) 253 267.2 250.2254.9 244.74 244.80 Crystallinity (%) 87.23 92.13 86.29 87.89 84.3984.41 GPC M_(n) 6776 7613 12764 14377 M_(w) 51377 45924 96923 69182M_(z) 128954 112444 280629 163561 Polydispersity Index 7.58 6.03 7.594.81 (M_(w)/M_(n)) Hexane Extractables (%)- 0.53 0.57 0.21 0.53 Plaque

TABLE 3 Polyethylene Homopolymer Composition Component PropertiesExample No. Inv. 1 Inv. 2 Comp. 3 Comp. 4 Density (g/cm³) 0.9662 0.96750.966 0.968 I₂ (g/10 min) 12.2 20.4 1.2 6 Stress Exponent 1.27 1.26 1.381.27 MFR (I₂₁/I₂) 33.2 32.5 57 33 Mw/Mn 7.58 6.03 7.59 4.81 FirstEthylene Homopolymer Weight fraction 0.536 0.535 0.47 0.515 Mw 10832392663 177980 115059 I₂ (g/10 min) 0.64 1.18 0.09 0.51 SCB1/1000 C 0 0 00 Density, d1 (g/cm³) 0.9506 0.952 0.9464 0.95 Second EthyleneHomopolymer Weight fraction 0.464 0.465 0.53 0.485 Mw 8685 8620 1339413105 I₂ (g/10 min.) 12306 12674 2264.0 2465.0 SCB2/1000 C 0 0 0 0Density, d2 (g/cm³) 0.9724 0.9725 0.9685 0.9687 Estimated (d2-d1), g/cm³0.0218 0.0205 0.0221 0.0187

TABLE 4 Plaque Properties Comp. Comp. Example No. Inv. 1 Inv. 1* Inv. 2Inv. 2* 3 4 Tensile Properties (Plaques) Elong. at Yield (%) 7 6 4 4 7Elong. at Yield Dev. (%) 0.1 0.7 0.1 0.5 0 Yield Strength (MPa) 33.534.8 32.9 34.6 34.2 Yield Strength Dev. (MPa) 0.1 0.2 0.9 1 0.4 UltimateElong. (%) 10 6 4 4 7 Ultimate Elong.Dev. (%) 0.1 0.7 0.1 0.5 0 UltimateStrength (MPa) 32.3 34.8 32.9 34.6 34.2 Ultimate Strength Dev. (MPa) 10.2 0.9 1 0.4 Sec Mod 1% (MPa) 1751.1 1974 1870.1 1997 1792 1996 Sec Mod1% (MPa) Dev. 69.6 31 34 61 165 109 Sec Mod 2% (MPa) 1280.8 1391 13381435 1233 1365 Sec Mod 2% (MPa) Dev. 17.9 15 11 34 33 29 Youngs Modulus(MPa) 2543 2790.1 Youngs Modulus (MPa) Dev. 477.1 558.4 FlexuralProperties (Plaques) Flex Secant Mod. 1% (MPa) 1853 1994 1882 2241 18561940 Flex Sec Mod 1% (MPa) Dev. 62 126 38 94 79 57 Flex Secant Mod. 2%(MPa) 1535 1652 1549 1817 1553 1580 Flex Sec Mod 2% (MPa) Dev. 42 87 1564 29 40 Flex Tangent Mod. (MPa) 2136 2276 2190 2587 2167 2309 FlexTangent Mod. Dev. 94 175 111 147 191 147 (MPa) Flexural Strength (MPa)48.7 51.6 49.5 54.8 48.5 49.1 Flexural Strength Dev. (MPa) 0.6 1.6 0.61.5 0.4 1.3 Impact Properties (Plaques) Izod Impact (ft-lb/in) 0.5 0.4 21.4 Environmental Stress Crack Resistance ESCR Cond. B at 100% CO- 0 0<16 4 630 (hrs) Miscellaneous VICAT Soft. Pt. (° C.)-Plaque 125 123.6128.4 127.4 Heat Deflection Temp. (° C.) 80.7 85.4 77.2 76.2 @66 PSI

Method of Making Compression Molded Film

A laboratory scale compression molding press Wabash G304 from Wabash MPIwas used to prepare compression molded film from the inventive andcomparative polyethylene homopolymer compositions. A metal frame ofrequired dimensions and thickness was filled with a measured quantity ofresin (e.g. pellets of a polyethylene homopolymer composition) andsandwiched between two polished metal plates. The measured polymerquantity used was sufficient to obtain the desired film thickness.Polyester sheets (Mylar) were used on top of the metal backing plates toprevent the sticking of the resin to the metal plates. This assemblywith the resin was loaded in the compression press and preheated at 200°C. under a low pressure (e.g. 2 tons or 4400 lbs per square foot) forfive minutes. The platens were closed and a high pressure (e.g. 28 tonsor 61670 lbs per square foot) was applied for another five minutes.After that, the press was cooled to about 45° C. at a rate of about 15°C. per minute. On completion of the cycle, the frame assembly was takenout, disassembled and the film (or plaque) was separated from the frame.Subsequent tests were done after at least 48 hours after the time atwhich the compression molding was carried out.

Determination of the Oxygen Transmission Rate (OTR) of a CompressionMolded Film Using a Masking Method

The oxygen transmission rate (OTR) of the compression-molded film wastested using an OX-TRAN® 2/20 instrument manufactured by MOCON Inc,Minneapolis, Minn., USA using a version of ASTM F1249-90. The instrumenthas two test cells (A and B) and each film sample was analyzed induplicate. The OTR result reported is the average of the results fromthese two test cells (A and B). The test is carried out at a temperatureof 23° C. and at a relative humidity of 0%. Typically, the film samplearea used for OTR testing was 100 cm². However, for barrier testing offilms where there is a limited amount of sample, an aluminum foil maskis used to reduce the testing area. When using the mask, the testingarea is reduced to 5 cm². The foil mask had adhesive on one side towhich the sample was attached. A second foil was then attached to thefirst to ensure a leak free seal. The carrier gas used was 2% hydrogengas in a balance of nitrogen gas and the test gas was ultra high purityoxygen. The OTR of the compression molded films were tested at thecorresponding film thickness as obtained from the compression moldingprocess. However, in order to compare different samples, the resultingOTR values (in units of cm³/100 in²/day) have been normalized to a filmthickness value of 1 mil.

Determination of the Water Vapor Transmission Rate (WVTR) of aCompression Molded Film Using a Masking Method

The water vapor transmission rate (WVTR) of the compression-molded filmwas tested using a PERMATRAN® 3/34 instrument manufactured by MOCON Inc,Minneapolis, Minn., USA using a version of ASTM D3985. The instrumenthas two test cells (A and B) and each film sample was analyzed induplicate. The WVTR result reported is the average of the results fromthese two test cells (A and B). The test is carried out at a temperatureof 37.8° C. and at a relative humidity of 100%. Typically, the filmsample area used for WVTR testing was 50 cm². However, for barriertesting of films where there was a limited amount of sample, an aluminumfoil mask was used to reduce the testing area. When using the mask, thetesting area was reduced to 5 cm². The foil mask has adhesive on oneside to which the sample was attached. A second foil was then attachedto the first to ensure a leak free seal. The carrier gas used was ultrahigh purity nitrogen gas and the test gas is water vapor at 100%relative humidity. The WVTR of the compression molded films were testedat the corresponding film thickness as obtained from the compressionmolding process. However, in order to compare different samples, theresulting WVTR values (in units of grams/100 in²/day) have beennormalized to a film thickness value of 1 mil.

The barrier properties (OTR and WVTR) of pressed films made fromcomparative and inventive polyethylene compositions are provided inTable 5.

TABLE 5 OTR and WVTR Properties of Compression Molded Films Comp. Comp.Example No. Inv. 1 Inv. 1* Inv. 2 Inv. 2* 3 4 WVTR-thickness (mil) 2.52.2 2.4 1.5 2.7 2.4 WVTR g/100 IN²/Day 0.1036 0.0773 0.0949 0.08650.0478 0.0617 (relative humidity = 100%, 37.8° C., atm) WVTR in g/100IN²/Day- 0.2590 0.1701 0.2278 0.1298 0.1291 0.1481 normalized thickness(1 mil) OTR-thickness (mil) 2.5 2.2 2.4 1.5 2.7 2.4 OTR in CC/100IN²/Day 31.93 29.4 31.22 28.79 21.14 28.45 (relative humidity = 0%, 23°C., atm) OTR in CC/100 IN²/Day- 79.83 64.68 74.93 43.19 57.08 68.28normalized thickness (1 mil)

As can been seen from the data in Table 5, as well as FIGS. 2 and 3, thefilms made from the nucleated inventive compositions (Examples 1* and2*) had OTR and VVTR values which were comparable to films made from thecomparative compositions when similarly nucleated (Examples 3 and 4),even though the inventive resins had higher melt indexes (i.e. lowermolecular weights). Indeed, film made from inventive Example 2* hadsuperior (i.e. lower) OTR values than film made from the comparativecompositions (Examples 3 and 4). Higher melt indices are useful for castfilm production as it helps with processability and production linetimes.

Method of Making a Closure by Injection Molding

Nucleated versions of the Inventive homopolymer compositions as well asthe comparative resins were made into closures using an injectionmolding process. A Sumitomo injection molding machine and 2.15-gram PCO(plastic closure only) 1881 carbonated soft drink (CSD) closure mold wasused to prepare the closures herein. A Sumitomo injection moldingmachine (model SE75EV C250M) having a 28 mm screw diameter was used. The4-cavity CSD closure mold was manufactured by Z-moulds (Austria). The2.15-gram PCO 1881 CSD closure design was developed by UniversalClosures Ltd. (United Kingdom). During the closure manufacturing, fourclosure parameters, the diameter of the top of the cap, the bore sealdiameter, the tamper band diameter and the overall cap height, weremeasured and ensured to be within quality-control specifications.

An International Society of Beverage Technologists (ISBT) voluntarystandard test method was used to determine the closure dimensions. Thetest used involves the selection of a mold cavity and the measurementson at least 5 closures made from that particular cavity. At least 14dimensional measurements were obtained from closures that were aged forat least 1 week from the date of production. The closure dimensionmeasurements were performed using a Vision Engineering, Swift Duo dualoptical and video measuring system. All measurements were taken using10× magnification and utilizing METLOGIX® M video measuring systemsoftware (see METLOGIX M³: Digital Comparator Field of View Software,User's Guide).

The closures were formed by injection molding, and the injection-moldingprocessing conditions are given in Table 6.

TABLE 6 Injection Molding Processing Conditions Example No. Inv. 1* Inv.2* Comp. 3 Comp. 4 Closure No. 1 2 3 4 Additives (Color & NaturalNatural Red Red Formulation) Part Weight (g) 8.6 8.6 8.6 8.6 InjectionSpeed (mm/s) 45 45 125 125 Cycle time (s) 4.09 4.34 4.12 3.65 Fillingtime (s) 0.639 0.617 0.245 0.245 Dosing time (s) 1.814 1.78 1.99 1.82Minimum Cushion (mm) 9.76 9.76 9.93 9.93 Filling peak pressure (psi)8660 7087 13829 14309 Full peak pressure (psi) 8670 7095 13829 14309Hold end position (mm) 12.39 11.53 11.65 11.44 Hold Pressure Setpoint(Psi) 2050 2000 4350 5700 Clamp force (ton) 20 20 19.78 19.70 Fill startposition (mm) 38.49 37.51 40.43 40.43 Dosing back pressure (psi) 833 830822 833 Pack pressure (psi) 8662 7038 13752 14222 Filling time 1 (s)0.64 0.616 0.248 0.248 Temperature zone 1 (° C.) 180 180 210 180Temperature zone 2 (° C.) 185 185 215 185 Temperature zone 3 (° C.) 190190 220 190 Temperature zone 4 (° C.) 200 200 230 200 Temperature zone 5(° C.) 200 200 230 200 Mold temperature 10 10 10 10 stationary (° C.)

Oxygen Transmission Rate (OTR) of an Injection Molded Closure

To measure the oxygen transmission rate through a closure ASTM D3985(Standard Test Method for Oxygen Gas Transmission Rate Through PlasticFilm and Sheeting Using a Coulometric Sensor) was adapted as follows.

First the closure's tamper evident band removed. Next, the bottom edgeof the closure was lightly roughed with sandpaper (for better adhesionto the epoxy) and then the closure was epoxied (using DEVCON® 2 partepoxy) to a testing plate so as to cover an outlet tube (for sweep gas)and inlet tube for N2 introduction. The epoxy was allowed to dryovernight. One of the two gas tubes protruding into the closure interiorcarries inlet nitrogen gas flowing into the closure interior (nitrogenfeed line), while the other one carries sweep gas (e.g. nitrogen pluspermeates from the atmosphere surrounding the closure) out of theclosure interior and into a detector. If any oxygen present in theatmosphere is permeating the closure walls it is detected as a componentwithin the N2 exiting the closure interior as sweep gas. Theplate/closure/tubing apparatus is connected to an OX-TRAN low rangeinstrument (PERMATRAN-C® Model 2/21 MD) with the testing plate placed inan environmental chamber controlled at a temperature of 23° C. Abaseline measurement for the detection of atmospheric oxygen is alsotaken by using an impermeable aluminum foil (in parallel with theclosure) for a side by side comparison of permeability. The oxygenpermeability of the closure is reported as the average oxygentransmission rate in units of cm³/closure/day.

The oxygen barrier properties of injected molded closures made fromcomparative and inventive polyethylene homopolymer compositions, all ofwhich were nucleated are provided in Table 7.

TABLE 7 Example Closure OTR Average No. No. (cm³/closure/day) Test GasInv. 1* 1 0.0012 ambient air (20.9% oxygen) Inv. 2* 2 0.0009 ambient air(20.9% oxygen) Comp. 3 5 0.0012 ambient air (20.9% oxygen) Comp. 4 60.0017 ambient air (20.9% oxygen)

As can been seen from the data in Table 7 and FIG. 4, the closures madefrom the inventive resins had OTR values which were comparable to orbetter than closures made from the comparative resins which weresimilarly nucleated, even though the inventive resins have higher meltindexes (i.e. lower molecular weights). Higher melt indices are usefulfor caps and closures production as it helps with production line cycletimes, especially during the production of injection molded closures.Also, the relatively low OTR values provide advantages in themanufacture of articles which may benefit from good barrier properties,such as for example a cap or closure for a bottle, container or the likeor a fitment for a pouch or the like.

INDUSTRIAL APPLICABILITY

The present disclosure provides polyethylene homopolymer compositionswhich have good barrier properties, and which can be used to manufacturefilms or molded articles such as a closure for bottles.

1. A polyethylene homopolymer composition, the polyethylene homopolymercomposition comprising: (1) 10 to 90 weight % of a first ethylenehomopolymer having a density, d¹ of from 0.943 to 0.975 g/cm³, a meltindex, I₂ ¹ of from 0.01 to 10 g/10 min, and a molecular weightdistribution, Mw/Mn of less than 3.0; and (2) 90 to 10 weight % of asecond ethylene homopolymer having a density, d² of from 0.950 to 0.985g/cm³, a melt index, I₂ ² of at least 500 g/10 min, and a molecularweight distribution, M_(w)/M_(n) of less than 3.0; wherein the ratio ofthe melt index, I₂ ² of the second ethylene homopolymer to the meltindex, I₂ ¹ of the first ethylene homopolymer is at least 50, andwherein the polyethylene homopolymer composition has a weight averagemolecular weight, M_(w) of ≤75,000, a high load melt index, I₂₁ of atleast 200 g/10 min, and a molecular weight distribution, M_(w)/M_(n) offrom 4.0 to 12.0.
 2. The polyethylene homopolymer composition of claim 1wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least
 100. 3. The polyethylene homopolymer composition of claim 1wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least
 1000. 4. The polyethylene homopolymer composition of claim 1wherein the ratio of the melt index, I₂ ² of the second ethylenehomopolymer to the melt index, I₂ ¹ of the first ethylene homopolymer isat least
 5000. 5. The polyethylene homopolymer composition of claim 1wherein the density, d² of the second ethylene homopolymer is higherthan the density, d¹ of the first ethylene homopolymer.
 6. Thepolyethylene homopolymer composition of claim 5 wherein the density, d²of the second ethylene homopolymer is less than 0.035 g/cm³ higher thanthe density, d¹ of the first ethylene homopolymer.
 7. The polyethylenehomopolymer composition of claim 5 wherein the density, d² of the secondethylene homopolymer is less than 0.030 g/cm³ higher than the density,d¹ of the first ethylene homopolymer.
 8. The polyethylene homopolymercomposition of claim 1 wherein the first ethylene homopolymer has adensity, d¹ of from 0.946 to 0.965 g/cm³.
 9. The polyethylenehomopolymer composition of claim 1 wherein the second ethylenehomopolymer has a density, d² of from 0.955 to 0.980 g/cm³.
 10. Thepolyethylene homopolymer composition of claim 1 wherein the first andsecond ethylene homopolymers each has a molecular weight distribution,M_(w)/M_(n) of less than 2.5.
 11. The polyethylene homopolymercomposition of claim 1 wherein the first and second ethylenehomopolymers are made with a single site catalyst.
 12. The polyethylenehomopolymer composition of claim 1 wherein the polyethylene homopolymercomposition has a density of from 0.950 to 0.980 g/cm³.
 13. Thepolyethylene homopolymer composition of claim 1 wherein the polyethylenehomopolymer composition has a density of from 0.961 to 0.975 g/cm³. 14.The polyethylene homopolymer composition of claim 1 wherein thepolyethylene homopolymer composition has a high load melt index, I₂₁ ofgreater than
 300. 15. The polyethylene homopolymer composition of claim1 wherein the polyethylene homopolymer composition has a melt index, I₂of ≥3 g/10 min.
 16. The polyethylene homopolymer composition of claim 1wherein the polyethylene homopolymer composition has a melt index, I₂ offrom 5 to 40 g/10 min.
 17. The polyethylene homopolymer composition ofclaim 1 wherein the polyethylene homopolymer composition has a molecularweight distribution, M_(w)/M_(n) of from 4.0 to 10.0.
 18. Thepolyethylene homopolymer composition of claim 1 wherein the polyethylenehomopolymer composition has a bimodal profile in a GPC chromatograph.19. The polyethylene homopolymer composition of claim 1 wherein thepolyethylene composition has a weight average molecular weight, M_(w) ofless than 70,000.
 20. The polyethylene homopolymer composition of claim1 wherein the polyethylene homopolymer composition has a weight averagemolecular weight, M_(w) of ≤65,000.
 21. The polyethylene homopolymercomposition of claim 1 wherein the polyethylene homopolymer compositionhas a number average molecular weight, M_(n) of less than 20,000. 22.The polyethylene homopolymer composition of claim 1 wherein thepolyethylene homopolymer composition has a melt flow ratio, I₂₁/I₂ ofless than
 45. 23. The polyethylene homopolymer composition of claim 1wherein the polyethylene homopolymer composition has a hexaneextractables value of less than 2 wt %.
 24. The polyethylene homopolymercomposition of claim 1 wherein the polyethylene homopolymer compositionfurther comprises a nucleating agent.
 25. The polyethylene homopolymercomposition of claim 25 wherein the nucleating agent is a salt of adicarboxylic acid compound.
 26. The polyethylene homopolymer compositionof claim 26 wherein the polyethylene homopolymer composition comprisesfrom 20 to 4000 ppm of the nucleating agent based on the combined weightof the first ethylene homopolymer and the second ethylene homopolymer.27. An injection molded article comprising the polyethylene homopolymercomposition of claim
 1. 28. A compression molded article comprising thepolyethylene homopolymer composition of claim
 1. 29. A closurecomprising the polyethylene homopolymer composition of claim
 1. 30. Afilm comprising the polyethylene homopolymer composition of claim
 1. 31.A cast film comprising the polyethylene homopolymer composition ofclaim
 1. 32. The polyethylene homopolymer composition of claim 1,wherein the polyethylene homopolymer composition is made by a processcomprising contacting at least one single site polymerization catalystsystem with ethylene under solution polymerization conditions in atleast two polymerization reactors.
 33. A process to prepare apolyethylene homopolymer composition, the polyethylene homopolymercomposition comprising: (1) 10 to 90 weight % of a first ethylenehomopolymer having a density, d¹ of from 0.943 to 0.975 g/cm³, a meltindex, I₂ ¹ of from 0.01 to 10 g/10 min, and a molecular weightdistribution, Mw/Mn of less than 3.0; and (2) 90 to 10 weight % of asecond ethylene homopolymer having a density, d² of from 0.950 to 0.985g/cm³, a melt index, I₂ ² of at least 500 g/10 min, and a molecularweight distribution, M_(w)/M_(n) of less than 3.0; wherein the ratio ofthe melt index, I₂ ² of the second ethylene homopolymer to the meltindex, I₂ ¹ of the first ethylene homopolymer is at least 50, andwherein the polyethylene homopolymer composition has a weight averagemolecular weight, M_(w) of ≤75,000, a high load melt index, I₂₁ of atleast 200 g/10 min, and a molecular weight distribution, M_(w)/M_(n) offrom 4.0 to 12.0; the process comprising contacting at least one singlesite polymerization catalyst system with ethylene under solutionpolymerization conditions in at least two polymerization reactors. 34.The process of claim 33 wherein the at least two polymerization reactorscomprise a first reactor and a second reactor configured in series. 35.A polymer composition comprising from 1 to 100 percent by weight of apolyethylene homopolymer composition, the polyethylene homopolymercomposition comprising: (1) 10 to 90 weight % of a first ethylenehomopolymer having a density, d¹ of from 0.943 to 0.975 g/cm³, a meltindex, I₂ ¹ of from 0.01 to 10 g/10 min, and a molecular weightdistribution, Mw/Mn of less than 3.0; and (2) 90 to 10 weight % of asecond ethylene homopolymer having a density, d² of from 0.950 to 0.985g/cm³, a melt index, I₂ ² of at least 500 g/10 min, and a molecularweight distribution, M_(w)/M_(n) of less than 3.0; wherein the ratio ofthe melt index, I₂ ² of the second ethylene homopolymer to the meltindex, I₂ ¹ of the first ethylene homopolymer is at least 50, andwherein the polyethylene homopolymer composition has a weight averagemolecular weight, M_(w) of ≤75,000, a high load melt index, I₂₁ of atleast 200 g/10 min, and a molecular weight distribution, M_(w)/M_(n) offrom 4.0 to 12.0.
 36. The polymer composition of claim 35 wherein thepolyethylene homopolymer composition further comprises a nucleatingagent.
 37. The polymer composition of claim 36 wherein the wherein thenucleating agent is a salt of a dicarboxylic acid compound.
 38. Thepolymer composition of claim 37 wherein the polyethylene homopolymercomposition comprises from 20 to 4000 ppm of the nucleating agent basedon the combined weight of the first ethylene homopolymer and the secondethylene homopolymer.
 39. The polyethylene homopolymer composition ofclaim 24, which when made into a PCO 1881 CSD closure, has an OTR ofless than 0.0025 cm³/closure/day.
 40. A film comprising the polyethylenehomopolymer composition of claim 24 and a having a normalized OTR of ≤80cm³/100 in²/day.
 41. A film comprising the polyethylene homopolymercomposition of claim 24 and having a normalized WVTR of ≤0.250 g/100in²/day.